Brief Industry Stories - Page 1
Forum section: electronics / general

author: Excavatoree
author_rank: Frequent Contributor
timestamp: May 22, 2013, 01:33:22 pm
content: I didn't want to start a new thread, but I couldn't find one that was suitable. So, I thought I'd start a thread for brief industry stories that don't deserve their own thread. If anyone feels this should be deleted, I won't argue.My company has design offices in several locations. One location is known for wiring harness mistakes. I've spent many a hot afternoon on a machine, sorting out which wires were in the wrong place and moving them to the correct place.We have a wire harness vendor that is known for ignoring the design specifications, and putting the wires in any connector cavity they like. Again, this causes much frustration and many re-working nightmares.One day, I got an e-mail that said: "Excavatoree, we designed harness blah-blah with a mistake, wire X and Y were reversed. However, the harness vendor reversed these wires when they built it, so it came out correctly."I know both the vendor and the designers were upset that each had canceled the others mistake, and I didn't have to make any re-work arrangements.

author: SeanB
author_rank: Super Contributor
timestamp: May 22, 2013, 04:01:36 pm
content: I see you use the same monkeys that build Boeing wiring looms..........

author: Excavatoree
author_rank: Frequent Contributor
timestamp: August 13, 2013, 08:38:55 pm
content: I just got a message from our service support folks here at excavatoree-company. Among other things, he mentioned that "The fuse was blown, so the mechanic installed a paper clip and burned the wiring harness from the front of the machine to the back."Honestly, what idiot would do that? What did this moron think would happen? Worse, I bet we send him a new harness free and paid him to change it under warranty. Good Grief.Sorry everyone, just had to vent a bit.

author: Neilm
author_rank: Super Contributor
timestamp: August 13, 2013, 09:10:05 pm
content: I remember we had a device returned for a warranty claim. It had some high voltage in it (100kV) and the user had decided he wanted to check what was on the terminals and had drilled holes through the case to get to them.Unfortunately they drilled through some of the wires inside. They also drilled the holes with the instrument plugged in - and apparently turned on.I only hope they were not generating voltage at the time.We didn't let them claim on the warranty and didn't send it back until they maid for the damage.Neil

author: KJDS
author_rank: Super Contributor
timestamp: August 13, 2013, 09:20:41 pm
content: Someone issued a drawing in third angle projection, but it had a first angle projection symbol on it. No-one spotted this, first prototypes made in house in third angle, all fine. A thousand off ordered from a supplier, made in third angle, rejected by their inspector, scrapped, remade in first angle and shipped to us correct to drawing. Of course our boards didn't fit. Needed scrapping and remaking as originally made.At another place, a director asked me how testing of a new board was going. I replied it was fine, meaning that I'd yet to see smoke and I knew that I could adjust the component values for it to meet spec. The director decided that "fine" meant he could order 700 off and blame me when there were 11 component changes per board needed.At another place, I asked the machine shop foreman if there was any chance of my housings being ready that evening as it was essential that my technicians had them first thing in the morning. I got to tap the 1500 holes myself on a late shift.At another place, when pen plotters were how you recorded performance, I know someone who was 9000 plots through the 14000 required for qualification when the project was cancelled.They are just a few engineering tales. I daren't start on what I've seen purchasing, manufacturing, stores etc do or I could be here all night, though i should mention the customer visit to discuss why some of our units had a high failure rate in the field. Coincidently, we received some field returns that morning, one of which their field monkey had fitted the D-type connector attached upside down, cut off their wring harness as he couldn't remove the connector and sent it back to us.

author: dfmischler
author_rank: Frequent Contributor
timestamp: August 13, 2013, 10:46:42 pm
content: I remember running into the head of our manufacturing group one day. He was all excited. He said, "We've completely changed our production standards. We now work to MIL-TFD-41C." I said, "Larry, I never heard of MIL-TFD-41C. It sounds like another military standard. What is it?" He beamed, and explained that it is sort of an acronym for "Make It Like The Fucking Drawing for once." I knew he had set me up, but I laughed anyway.

author: Stonent
author_rank: Super Contributor
timestamp: August 13, 2013, 10:55:55 pm
content: Quote from: Excavatoree on August 13, 2013, 08:38:55 pmhttp://www.snopes.com/autos/techno/fuse.asp

author: dfmischler
author_rank: Frequent Contributor
timestamp: August 13, 2013, 10:56:57 pm
content: You'll like this one. The company I was working for had recently moved into a facility in New Jersey owned by another division. I think this was around 1988. I was in the lab working with one of the hardware designers on a prototype and we were having some trouble with a circuit so I told him I would get an inverter from the stock room. So I go over there and say, "I need a 74LS04". They said, "What's that? A chip?" Me, "Yeah." They said, "We don't have any chips like that." I'm thinking, "Oh, shit. What now?", but what I said was, "OK, show me what you've got" They seemed to have about 50 boxes of chips, none with numbers I recognized. They said, "Here, we got a box of these 8702's." I opened the box they gave me, and inside was a bunch of different kinds of chips sitting in dissipative foam, all with the date code "8702". They were not happy when I explained that they had sorted every chip in stock by date code and we needed them sorted by part number...

author: JuKu
author_rank: Frequent Contributor
timestamp: August 14, 2013, 08:00:54 am
content: I was once sent a batch of DSPs which in reality, were just the cases (no chip inside) that were the result of the factory testing their new printing process. Ok, the logo was fancy and that batch of the product was very easily sold.

author: Corporate666
author_rank: Unknown
timestamp: August 15, 2013, 02:32:36 am
content: We are located in a business part with a bunch of other companies - and over the years you get to know the people around.So one day a guy comes over from an adjacent business to ask if he can use one of the CNC machines to drill and tap some holes in this piece of metal. Well, we're not about to let someone else operate one of the machines, so we tell him to describe what he needs and we'll just do it for him.Keep in mind this guy works for a company that builds some very expensive robotic machines used in manufacturing for the sporting industry.He says that a machine has been damaged and they are replacing the mounting base for the linear rails, and he needs 4 drilled and tapped holes a certain distance apart and has the bolt that goes through this panel to mount it.Err, wait... if the bolt passes THROUGH this panel, then you mean you want clearance through holes on this one, right?Nope, he wants them tapped.But doesn't the bolt pass through this piece into another? Yes, he says.Well, you can't have two drilled/tapped pieces back to back - they won't line up and won't be flat.The guy starts to get a bit irritated and says this is what it needs.Ok, no problem - so we machine it.A while later, a bang is heard, followed by the guy coming back an hour later to ask if we can drill out the holes to be clearance through holes.When he installed his plate, it was sitting a millimeter or two high because the threads didn't line up so the plates were not flat.. and when the carriage of the machine shot across at 65 meters/minute, it crashed into the plate that was standing proud.So he needed to fix the plate and cover up the reason for the crash so they could bill the customer for the damaged carriage as well as the damaged mounting plate they were originally replacing.

author: Stonent
author_rank: Super Contributor
timestamp: August 15, 2013, 06:44:07 am
content: Guy I worked with about 15 years ago at a computer repair counter had a customer's computer on the counter and he had somehow wedged a PCI card in the ISA slot and couldn't figure out why it wasn't displaying anything on the monitor. It was just stuff like this on a daily basis that drove us to corner the boss and ask him to fire the guy. As Foghorn Leghorn would say "That boy's about as sharp as a bowling ball!"

author: Dajgoro
author_rank: Frequent Contributor
timestamp: August 15, 2013, 05:03:09 pm
content: Quote from: Stonent on August 15, 2013, 06:44:07 amI heard such stories at a local pc shop where a guy forced the motherboard power connector in the wrong direction and blew the motherboard.

author: SArepairman
author_rank: Frequent Contributor
timestamp: August 15, 2013, 07:33:08 pm
content: Anyone remember that post where some guy took a saw to his expensive videocard to fit it in a AGP slot?I think it was just BS for attention but it was pretty funny.*not on this forum

author: Spunky
author_rank: Regular Contributor
timestamp: August 15, 2013, 09:14:12 pm
content: When I worked in IT I used to see PCs assembled all the time with self tapping screws shorting out boards, wooden wedges instead of mounting brackets, and even double sided tape to hold drives in place. When I'd comment I would usually get the response "Oh it can't be that that's the problem, my husband built it and he's an engineer"I now work more with electricals and often get asked by electricians how to find out what's tripping the breaker or rcd, how to wire stuff into 3 phase, how to use their test meters, etc. It's not even funny that these folks are out there rewiring your house.

author: Legit-Design
author_rank: Frequent Contributor
timestamp: August 15, 2013, 09:28:53 pm
content: Quote from: Stonent on August 13, 2013, 10:55:55 pmhttp://en.wikipedia.org/wiki/MythBusters_(2004_season)#Episode_overviewCan a bullet be used as a fuse in a vehicle and will the bullet fire?Already tested, conclusion was that the casing shoots out, since actual bullet is heavier than the casing. There is a reason bullets are shot out of guns with barrels.

author: envisionelec
author_rank: Frequent Contributor
timestamp: August 15, 2013, 10:20:56 pm
content: Quote from: Spunky on August 15, 2013, 09:14:12 pmMaybe one that drives a train....

author: liquibyte
author_rank: Frequent Contributor
timestamp: August 15, 2013, 10:26:17 pm
content: QuoteI lived in a house in Florida and went to plug the vacuum in to do the dining room and the vacuum didn't come on. I figured the outlet was probably wired with a switch to the outlet so I flipped the one switch in the room and then the switch on the vacuum and the light came on. To this day, I can't figure out how someone could get something that wrong.

author: wraper
author_rank: Unknown
timestamp: August 16, 2013, 12:50:51 am
content: 5 years ago when I worked in authorized mobile phone repair shop, one guy asked Motorola part number for a special gasket that pushes BGA chip downwards so it regains broken solder joint.

author: Stonent
author_rank: Super Contributor
timestamp: August 16, 2013, 01:11:41 am
content: Quote from: Dajgoro on August 15, 2013, 05:03:09 pmWhile working there I had a customer demand a replacement and free install of a CPU. He ran the fan wires underneath the CPU between it and the socket and the board caught fire. And the sad part was, they did just that for him.

author: c4757p
author_rank: Super Contributor
timestamp: August 16, 2013, 01:22:02 am
content: It's always nice when a shop treats its customers well, but some places take "the customer's always right" ridiculously far...

author: Stonent
author_rank: Super Contributor
timestamp: August 16, 2013, 01:54:17 am
content: Quote from: c4757p on August 16, 2013, 01:22:02 amWe had another customer connect the 12v fan plug to the power switch header. Another board with burn marks. And yes we replaced that one for free as well.It was Fry's electronics by the way. I'm sure many of you in the US have heard of them or shopped there if you've been on the west coast or Texas.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: August 16, 2013, 02:00:47 am
content: Quote from: envisionelec on August 15, 2013, 10:20:56 pmBehind the bus factory where I used to work was a railroad track. I was with one of the guys on the assembly line, working on a bus parked out back. He was dead serious when he told me that he was waiting for one of the engineers to jump off of one of the trains and do a better job than the engineers we had. (other than me, of course, LOL)

author: dfmischler
author_rank: Frequent Contributor
timestamp: August 29, 2013, 03:06:54 pm
content: Around 1990 or so, I heard a bit of a fuss in the lab. One of my software guys (who happened to be Palestinian) was telling one of the hardware guys (who happened to be Israeli) that the hardware was a "piece of shit that didn't work", and that he was going to lunch now (11:00 AM) and hoped that the hardware was working when he got back. Now these were both smart, motivated guys who never discussed the politics of their homelands, and usually got along, but I was a little worried at where this was going.I was a little surprised when the hardware guy came to me a couple minutes later and said, "Sam is pissed. He says when he writes to the Dallas NVRAM on my new board that he can't read it back. How can that be? I took the write circuit straight from <names another board designed by another engineer>." I told him I would take a look. He grabbed a scope, and we set up an in-circuit emulator. The first thing I did was test the NVRAM with the normal routine we used for power-up RAM testing. It failed. So I set up a tight loop that wrote to a single location in the NVRAM.The address decoding seemed fine. The write line went low at the right time, but clearly stayed low past the end of the write cycle. The data hold requirement on the NVRAM was longer than the CPU could provide, so a one-shot had been used to time the write cycle. It should have been bringing the write line back up at least 10 ns before the end of the cycle, but instead was running past the end of data valid and storing random crap in the NVRAM. The clock on the new board ran faster and the designer didn't adjust the one-shot timing. So I was afraid we were going to have World War III and all it took to avoid it was a different capacitor value.Such is life in America

author: KJDS
author_rank: Super Contributor
timestamp: August 29, 2013, 04:41:26 pm
content: The new power supply design, a complex, multi-output switch mode beast with assorted complex functions had arrived from assembly and was ready for testing. The designer had the load ready and it was soon hooked up. A large pile of meters monitored all the voltages and currents and a scope was on hand to check ripple and for troubleshooting.When the mains was turned on all the outputs appeared on order, however panic ensured as smoke rose from the supply. What was happening?It is very very wrong, to run a long length of hose under the bench from the other end of the lab. It is even more wrong to blow cigarette smoke down the hose so that it appears under a new power supply design that is being tested for the first time.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: August 29, 2013, 04:59:58 pm
content: Quote from: KJDS on August 29, 2013, 04:41:26 pmVery wrong, but very funny.

author: SeanB
author_rank: Super Contributor
timestamp: August 29, 2013, 06:03:13 pm
content: Naughty, but even worse is to sneak craftily into the room as they are about to turn on a newly repaired unit and drop a big book on the floor as they turn on the power.As well we would take a signal generator, set the output at low level to the radio and then crank it up to full power, attach a long wire antenna and feed in an audio signal from another station. Great fun when you do this craftily at tea time so when they go back they tune the radio fruitlessly for an hour before the penny drops. Pretty good HP signal gen we had, it had a range of about 1km with a wire up to the roof.

author: Neilm
author_rank: Super Contributor
timestamp: August 29, 2013, 09:11:21 pm
content: Quote from: Excavatoree on August 29, 2013, 04:59:58 pmAgreed - very wrong. However, not quite as wrong deliberately putting a 10V electrolytic on a 28V supply backwards. Then getting your boss in to say "As instructed I haven't tested any of this new design just put it together." Then invite him to turn it on.Neil

author: bookaboo
author_rank: Frequent Contributor
timestamp: August 29, 2013, 09:35:22 pm
content: I once worked for a firm who employed the "other brother" as a director. Not qualified in any way and too brash to stick to sales where he belonged, among his efforts..- Suggesting a footswitch for a wheelchair access lift- Insisting adding a canbus module to a design should only take a day since its "two wires just like a doorbell" (he wasn't being wry or ironic either)- Dismantling an "broken" soldering iron after mistaking a roll of tinned wire for 60/40- Dressing down a trainee for fitting a panel plug to a mobile piece of equipment. The trainee correctly decided to provide the customer with a 230v cable socket and fit the plug to the equipment.... but "sockets go on walls plugs go on cables, get that f'ing changed"

author: ampdoctor
author_rank: Frequent Contributor
timestamp: August 29, 2013, 11:25:53 pm
content: Heres a real winner for ya! A number of years ago I had a fab shop produce a run of powder coated and silk screened steel enclosures for me. Well, somehow they managed to print the silkscreen upside down on the enclosures. In order to "save costs" and avoid running another lot some genius decided they would shot blast the powder coat off the enclosures and repaint them. You know what's coming right?! When I finally got the enclosures and opened the shipping containers, to my horror all the powder coating had flaked off!But that's OK, in order to try to "make it right" they offered to hand paint, with a brush brush mind you, all the spots where the coating had refused to adhere. Two days worth of phone calls and wrangling around and they finally agreed to make another run of enclosures. Needless to say I haven't used that company since.

author: TerraHertz
author_rank: Super Contributor
timestamp: August 30, 2013, 11:40:13 am
content: Sometime in the 70's I was working as a service tech in the Sydney Computerland store. One day another tech there was asked to fix a Qume daisy wheel printer. Now at that time these were the pinnacle of printer technology, and very, very expensive (on the scale of personal computer system prices.)He took all the cover panels off it, then needed to get at the bottom while testing it. So he balanced it on its rear end. On the edge of the workbench.It looked very unstable to me. About then lunchtime turned up, and as we were getting ready to leave I asked him if he was thinking of putting the Qume down flat while we were out. "No, it's fine!"Huh. Well OK if you think so. (I hadn't yet learned to take no shit from idiots.)Just as we'd left the room there was a horrible CRASH sound. RIP the Qume printer. Complex mechanical beasts don't like being dropped from bench height onto concrete.Another time while contracting, because my resume mentioned having experience with wire-wrapped gear, I was given a contract to wire-wrap a fairly serious prototype board for a large corporation that should have known better. They supplied me with a schematic from their extremely high pay 'design engineer'.One look at it and I knew this was going to be awkward. It had been produced by a total novice. Never Going To Work. For instance strobe decoding implemented with chains of nand gates, resulting in ridiculous, completely unworkable delay times.Querying them about such issues resulted in a snooty "our engineer is an expert, you just wire it up".Well the hourly rate was fine, so OK if you insist.I only heard a few snippets of news on how they went with debugging it. Apparently there was high drama, and it never did work. Ha ha... not my problem. They couldn't complain about wiring errors, there weren't any.It _amazes_ me what idiots get given jobs that adults should do.Another time, at a high profile company that made gaming industry related gear. I was working as a programmer (assembler code, on the metal), but my boss knew I was familiar with hardware design too. They had a project where some contractor had designed a 68000-based board, that was intended for a machine to be installed in pubs, TAB, etc. The designers apparently were having trouble getting it going, I had a logic analyzer with a 68000 emulator, could I have a look at the board please? I said OK, how bad could it be? Probably something simple.Turned out the guy who designed it was 'old school', and had decided 4-layer boards with ground and power planes were an unnecessary and frivolous expense. He'd run a grid of nice fat power and ground rails across the board, with plenty of bypass 0.1uF ceramics, then routed traces around that. Apparently he'd never heard the phrase 'ground bounce', and did not understand HF digital design at all.So whenever the 68000 happened to flip a lot of its many address lines at once, the result wasn't what you'd hope for. It was easily demonstrated with the analyzer.But then.... when I told management the board design was a write off, and needed to be redone in 4 layer, they refused to believe it. Kept trying to patch the existing board to make it work. The horrible thing even got a few out into the market - where they proved to be hopelessly unreliable and were soon abandoned. Told you so. 'Mysterybet' - that's what the machine was called. A couple of years ago I found one in the basement of an abandoned building, and salvaged the CPU board from it. Same bit of junk. Feast your eyes on the pics - a 68000 CPU board with no ground plane. How rare!The board is also ruined by the 'old NiCad battery leaked' syndrome, hence the corrosion.Oh man, I can recall dozens of stories like that. I'll add some more later.

author: FrankBuss
author_rank: Unknown
timestamp: August 30, 2013, 05:03:27 pm
content: Quote from: TerraHertz on August 30, 2013, 11:40:13 amThe Amiga 2000 used a 2 layer board:http://www.amigahistory.co.uk/a2000.html#a2000bI can't find any reference for the A500, but probable this was a 2 layer board, too. Was sold successfully a millionfold.

author: marshallh
author_rank: Unknown
timestamp: August 30, 2013, 05:33:50 pm
content: You can get away with 2 layer in some cases if your board is not very dense, you can afford to space some things apart, in which case you run solid copper pours under all fast edge rate signals. As long as there are solid reference planes where it counts, it doesn't matter. It is impractical to shoot for 50ohm on 2layer though with digital because of the widths required.That said, I havent done a 2layer in quite some time

author: uoficowboy
author_rank: Regular Contributor
timestamp: August 31, 2013, 02:28:43 am
content: Quote from: liquibyte on August 15, 2013, 10:26:17 pmSo a light and outlet were on the wrong switch? I don't see what is wrong with that.I recently was in an apartment where the oven (gas, but uses electric power for controls, clock, timer, etc.) was on an outlet that was switched. The microwave was also on the same switched outlet. Further, there is a lightbulb that is on the same switch. Finally, the garbage disposal, which has its own switch, is on that same switch (in other words - both switches have to be on to operate the garbage disposal).I eventually just installed a pull switch socket where the light is and now the switch is left on always. But man - whoever wired that is, well, special.

author: rexxar
author_rank: Frequent Contributor
timestamp: August 31, 2013, 02:54:35 am
content: Quote from: uoficowboy on August 31, 2013, 02:28:43 amThe house I grew up in had a switch that tripped a circuit breaker when flipped. I can only assume some idiot wired hot and neutral across the thing!Although, it was good fun when I was pissed off at my brother, flip the switch while he's playing video games, and he was too scared of the basement to go flip the breaker back.

author: NiHaoMike
author_rank: Super Contributor
timestamp: August 31, 2013, 03:40:58 am
content: In my senior design class, I decided to let my teammates do the firmware for the power measurement circuit. That turns out to be a big mistake. They used a rather convoluted floating point algorithm and were wondering why it got such a poor accuracy, on an Arduino with a breadboarded "AFE". It took me a few hours to understand what they were doing and port the code to fixed point for a dsPIC. (At least I knew their hardware design wasn't going to work very well so I made my own!) I also let them do the "practice" board design, which was similarly hopeless with several inch long crystal traces. (Fortunately, it didn't have to do much to get credit and I was able to use the internal RC oscillator on the PIC.)Then there was that other team who didn't take my advice to take apart some walkie talkies to use the receivers and transmitters built in and also take apart some old modems to use the signal processing circuits inside them. They ended up without a working prototype to show. (Tiffany Yep shows that there really is a lot to digital communications, and she doesn't even build the hardware!)

author: TerraHertz
author_rank: Super Contributor
timestamp: August 31, 2013, 09:28:44 am
content: Quote from: FrankBuss on August 30, 2013, 05:03:27 pmLooking at pics on the net of the Amiga 2000 board, the top layer is about 50% solid copper pour. Yes, you can get away with 2-layer in such designs if there's lots of ground cross section where it's needed.But more critically, the MysteryBet board used a 68HC000. Which has much beefier pin drivers. Hence worse ground bounce.Did you look at that back-lit PCB pic I posted? Look at how sparse the ground traces are, and the weird routes they take. When I said 'lots of fat traces' I was being sarcastic.Oh, and the circuit is also an interesting mix of LS, HC and HCT logic. I can't recall if I checked every interconnection for incompatibilities, but LS to HC is a no-no. Itsort ofworks, depending on temp, ambient EMI and the phase of the moon, due to LS logic H output being only just above input threshold for HC.Actually there's a few tales there too. I lost count of how many times I had to fix that 74LS to 74HC mistake in other people's designs.

author: SeanB
author_rank: Super Contributor
timestamp: August 31, 2013, 09:37:46 am
content: Only works if you have pull up resistors on the bus for the HC parts, then they do work reliably, but not to full speed.

author: TerraHertz
author_rank: Super Contributor
timestamp: August 31, 2013, 10:03:09 am
content: This one is not electronics related, but still funny.At one time I was doing some contract work on a certain ship of a certain navy that shall remain nameless (but was docked in Sydney.)The ship was in port for a refit. Again. Because it had suffered an unfortunate mishap with one of the ship's four main diesel engines.The ship had been in refit just shortly before, and there'd been some major service work done on the engines. This involved cutting through the decking to extract the engines, sending them off for stuff like crankshaft regrinds, cylinder and piston refurbishments, and so on. The engines were put back in, decks welded shut again, and the engines connected up and tested by navy staff. Then the ship merrily set off on duty.Some days out at sea, there was a mighty crash sound, shaking the whole ship. One of the engines had suddenly and completely seized. These are big engines, lots of mass moving around, which complains a lot when suddenly stopped.What had happened: when navy persons were reconnecting lubricating oil lines, someone had neglected to remove a bit of rag stuck in the end of an oil line, feeding one of the cylinder liners. Then while the ship was under way, no one had noticed that the temperature gauge for one cylinder was going 'a bit high'. Eventually the piston seized in the liner.But that wasn't enough to stop the engine. The crankshaft kept turning, pulling the con-rod and gudgeon pin out of the piston. The rod was then flailing around in the engine casing. Then the gudgeon pin slipped out of the end of the con-rod. It got thrown around in the crankshaft casing for few moments, until... becoming wedged end-on between the crankshaft counterweight and the bottom casting holding the piston liner. THAT'S when the engine suddenly came to a halt.The whole 'cut the engine out of the ship, and refurbish it' had to be repeated.And here is a picture. The cylinder liner, piston and con-rod had been removed already. I don't think in one piece. They had been unable to hammer the gudgeon pin free.

author: SeanB
author_rank: Super Contributor
timestamp: August 31, 2013, 11:46:42 am
content: Reminds me of when I was an apy and my boss then was telling us of one day working on the line changing a hydraulic pressure transmitter. He had the old one out and the new one in and connected but not locked or tight, and the bell went for tea. During tea he heard engines start up, and wondered which chopper was going out, as his one was the only one on the line, and the rest were in the hanger and would need to be pushed out to take off. Walked out after tea and no chopper there, but coming in on the taxiway was a chopper streaming a mist all over. It stopped, and without a word he walked over to it, popped the ladder and climbed up to the top. Pilots saying a major leak, so he opened the cover again, picked up his tools from the floor there and carried on fitting the transmitter. OC comes over, and he calmly told him the pilots have to wash the entire chopper inside and out, as it is not his problem, then went to fill in the completed block in the logbook. They washed it without a second word.....Of course one day I was there and he went out on a quick flight to the mountains. 2 hours later no show, so we asked and they said there was a problem with the chopper and they were flying out some spares. He came back 4 hours later white, and said they had an engine fire and had to put down on the closest ground that was close to level. Turned out to be a 45 degree slope and all other than the one pilot had to hustle out with the chopper still streaming smoke and flame and grab rocks and boulders to chock the wheels before they stopped the engines and popped the fire bottle to put out the fire. Burst hydraulic line sprayed oil all over and that on the exhaust caught fire. Flew out a spare pipe, 100l of red Aeroshell and the right tools and changed it right there. Then flew back in it.

author: TerraHertz
author_rank: Super Contributor
timestamp: September 02, 2013, 01:39:51 am
content: Another time, working at a company that had been great fun and very satisfying to work at under the original owners, till they retired and sold the business. The new owners were Dilbert management types, and turned the entire operation to shit. It's amazing how stupidity at the top ripples down, as idiots hire underling idiots, and the management chain becomes full of nitwits.But, I was paying off a mortgage and it was 5 minutes drive from home, and well paid, so stayed. Bearing the pain. Some of which was quite comical, in a masochistic way. For instance...I'd been developing a PCI audio card, with the difference of having a fairly beefy output amplifier on the card. It was for poker machines, needed to drive speakers directly. The circuit ran off 12V (from the PCI slot) and had a few electrolytics. At the time I had a hand-wired prototype of the audio amp sitting on the bench, with a variable bench power supply providing the 12V DC, sig gen for audio source, and scope looking at the output. Nothing special.Turned everything off and went home for the evening.Came in the next morning and moments later one of the nitwits (who shall not remain anonymous - his name was Brian, who had recently been hired as my immediate boss) stormed into the room, furious. "What do you think you're doing!? You nearly put my eye out!!!"Eh? What?"Here! One of these capacitors on your circuit blew up! It hit me here!" (He pointed at a small mark on his cheek, just below his eye.) "I could have lost an eye!"But... how...?"I was looking at your circuit here, and it blew up!"Err... but they are 16V electros, running at 12V. Why did it..? What did you do?"I was just adjusting the power supply voltage. It shouldn't blow up!"Turns out by 'adjusting' he meant twisting the power supply voltage knob back and forth. The supply could put out up to 30V or something like that. He'd been leaning over the circuit with several 16V electros, while turning the supply up to some voltage well above 16V. A cap blew its can off, hit him in the face.I definitely wish it HAD hit him in the eye. WTF? This Brian clown was supposed to be an electrical engineer.And what's he doing, messing with my test setup anyway?There was something wrong with that guy. Another time he'd proudly related an 'engineering story' from his past. He'd been employed at one of the Hunter Valley coal-fired power stations, during original commissioning. When it came time to do a first test run of the main boiler water injection pump, they'd chosen this character to monitor the control room gauges, while the engineers running the test operated the pump motor from the panel near the motor. Now this was a big motor (I don't know the actual size, but let's say larger than man-sized.) The intake water pipe came down from some tank high up in the building. There was a pressure gauge on the pump intake pipe - one of the gauges Brian was supposed to watch, and hit the big red abort switch if anything odd happened.So they started the pump. The intake gauge pressure began to fall. And fall. Brian (the brain?) seemed to be really proud that he'd figured out there must be a problem with water getting from the supply tank to the top of the intake pipe. But did he hit abort? Nope. He just watched the pressure gauge fall and fall. To zero. Turns out someone had forgotten to open the manual valve on the top of the pipe. When the water in the pipe ran out, the motor and pump spun up and exploded. Total wrecks, fortunately no one killed.He stood there and told this story to me like he was somehow proud of understanding what was happening at the time. But he had one job...He was a very creepy man.Eventually I managed to get made redundant at that lunatic asylum (by the process of doing exactly what I was told, which resulted in nothing much getting done), and got my long service payout. Such a relief.A pic of that audio card:

author: c4757p
author_rank: Super Contributor
timestamp: September 02, 2013, 01:51:07 am
content: Quote from: TerraHertz on September 02, 2013, 01:39:51 amWhat? ...how? I don't even.... but.... how could he.... so stupid.... how.....oh screw it.... I'm going to drop out of school and become a hobo. This electronics thing isn't worth it.

author: IanB
author_rank: Super Contributor
timestamp: September 02, 2013, 02:45:03 am
content: Quote from: TerraHertz on September 02, 2013, 01:39:51 amYes, that's interesting in itself. Working at a plant once, there were two pumps side by side with the same duty, the A pump and the B pump. The A pump had an electric motor, which was very large, certainly bigger than man-sized. The B pump had a steam turbine to drive it, which was tiny, a couple of feet across. It looked rather incongruous with the two identical pumps side by side, when considering that the tiny steam turbine could produce the same output power as the huge electric motor.You will recognize this if you have ever worked with compressed air tools in a workshop. Compare the relative size and weight and output power of a compressed air drill with an electric drill.

author: kizzap
author_rank: Unknown
timestamp: September 02, 2013, 04:24:22 am
content: Quote from: IanB on September 02, 2013, 02:45:03 amAh but there is always the problem that you need an air source of some kind, so its not really portable.The only notable story I can think of, was when I was trying to do a university degree, in a practical course we had to do a series of power calculations reading a couple of meters connected to a transformer of some kind. Due to WH&S requirements, naturally we weren't allowed to connect anything up. To give us a challenge, the supervisor decided instead of telling us what each meter was, left the meters turned off and told us to figure out which one was which from the schematic. Within a minute, one of the other students had picked up the one meter specifically connected via the amperage range, proclaiming it to be the meter measuring one of the voltages we needed to measure. He was adamant too. Thankfully common sense prevailed and nothing released the magic smoke.-kizzap

author: NiHaoMike
author_rank: Super Contributor
timestamp: September 02, 2013, 04:39:15 am
content: Modern inverter drive motors can be quite small for their power output. For a given size, higher RPM gives more power. A 500W (continuous duty) switched reluctance motor (operating in the low 100kRPM range for a centrifugal compressor) in a hybrid air conditioner is smaller than a soda can.

author: SeanB
author_rank: Super Contributor
timestamp: September 02, 2013, 05:47:52 pm
content: The Dilbert PHB "engineer" needed a little introduction to safety Brickmaker style. I was told of the method the floor used to " fix" anybody that was an asshat and who was working with them and not improving. Wait for a jam in the inlet to the crusher, then send him in to clear it. When sufficiently cleared turn on the crusher and rod mill again, problem solved and you do not even get the large pry bar back at all.Another method is not printable.

author: brabus
author_rank: Frequent Contributor
timestamp: September 03, 2013, 09:27:14 am
content: FPGA team project.We decided to give an easy part of the job to a pretty dumb colleague, just to give him something to do, and avoid him to wander around in the office.The task was: "Hey, we need 'bout 1 kHz to refresh the 7-seg displays, can you provide the code for a simple clock divider? You can start from the 50 MHz main clock".What he did was mighty. He coded a VHDL divider with an exact 50.000-counter, which provided EXACTLY 1,000.000 Hz, quartz regulated, at the output.He used about 10% of FPGA resources.Just for the damn 1 kHz refresh rate.What we did was to thank him for the support, delete the code, and replace it with a simple 2^n divider - negligible resource consumption.But if we talk about FPGAs, we can really tell horrendous stories. People not understanding the basic concept of programmable logic, implementing a uC soft-IP core just to run the usual C code, route all the I/Os on the output pins, and make the damn thing becomede factoa uC! Why? WHY???

author: jeroen74
author_rank: Frequent Contributor
timestamp: September 03, 2013, 05:54:48 pm
content: That 50K divider, is like ten lines or so? I don't find the solution notthatstupid to be honest and certainly not facepalm worthy... IMO. I think there are far more facepalm worthy things you can do in an FPGA then a slightly over-engineered clock divider...

author: FrankBuss
author_rank: Unknown
timestamp: September 03, 2013, 06:17:46 pm
content: I implement this all the time with an exact counter, and usually with a generic parameter to pass the clock frequency, see e.g. this code by me:https://github.com/FrankBuss/YaGraphCon/blob/master/spartan3e/src/rs232_sender.vhdThis helps for re-usability, because you can use the same entity in other systems with other clocks as well, without changing it. Hacks like using binary dividers might make sense for low resource FPGAs or CPLDs, but an exact 50,000 counter maybe needs less than 1% of modern FPGAs.

author: megajocke
author_rank: Regular Contributor
timestamp: September 04, 2013, 05:00:14 am
content: Well, a 50000-counter (implemented as a 16 bit binary counter + reset comparator) shouldn't be that bad... but maybe it was one-hot coded, requiring 50k flip-flops?That would be quite an ugly implementation.

author: brabus
author_rank: Frequent Contributor
timestamp: September 04, 2013, 12:27:52 pm
content: Quote from: jeroen74 on September 03, 2013, 05:54:48 pmAs you may know, with VHDL the point is not "how many lines of code", but "how many FPGA resources do I need to do that".For example, a long-described look-up table can be easily resolved with a few logic blocks, while a state machine (you can write one in very few lines of code) easily requires more physical space.We had a Spartan 3-200, and we werepretty pretty tightwith this requirement.Hey FrankBuss, thanks a lot for your link!

author: jeroen74
author_rank: Frequent Contributor
timestamp: September 04, 2013, 06:39:01 pm
content: Of course, you can fill up the biggest Virtex 7 or Stratix 10 with a simple generate statement; that's how they fill up those beasts to mine bitcoinsI'm just pointing out that the solution by that obnoxiuos coworker is not that cringeworthy. I guess using on-chip tristate busses, inserting gates just for their delay to fix some timing issue, cascading PLLs, failing to synchronize inputs, or just as bad, synchronize all inputs of some bus instead of just the strobes or control lines, are far more facepalm worthyOne thing I saw at work recently, keeping an moving average along the lines of:sum<=prev_sample_0 + prev_sample_1 + .... goes on.... + prev_sample_63;prev_sample_0<=prev_sample_1;prev_sample_1<=prev_sample_2;...prev_sample_63<=new_input;output<=sum(63 downto 31);The writer apparently never heard of arrays, generate and for statements. Or that you can compute it much faster by using:Or by the same writer, duplicating exactly the same code four times, instead of making it a component, then instantiate that four times...

author: ah ffs
author_rank: Newbie
timestamp: September 04, 2013, 10:28:19 pm
content: Anyone else have any actual "industry stories", before this thread gets dragged off topic? I was enjoying those.

author: fcb
author_rank: Super Contributor
timestamp: September 04, 2013, 10:44:05 pm
content: I once asked a newly recruited EE (with a good 2-1) to build me a simple linear PSU, gave him a box of parts. Came back later and found him unwrapping the insulation from the toroidal txfmr - thought it was packaging.

author: ah ffs
author_rank: Newbie
timestamp: September 05, 2013, 12:34:52 am
content: Quote from: fcb on September 04, 2013, 10:44:05 pmCheers for that, I had quite a good chuckle. And I'm sure this fella had many other fine qualities and skills that justified his recruitment......perhaps.

author: dfmischler
author_rank: Frequent Contributor
timestamp: September 05, 2013, 12:54:03 am
content: In the late 80's I was working for a company that made stuff for government agencies. We built a lot of the stuff from the PCB's up. We liked ethernet, but it was still expensive to build, test, and integrate, and most facilities were not ready to use it extensively, so most of our devices communicated over serial links using opto-isolated current loop or differential interfaces for noise immunity. We were having a lot of trouble with equipment failing in a facility not too far from Chicago. We assumed that it was a software problem because if you powered the equipment down, then back up, it would operate normally again. Failures were often noticed at shift change (24-hour facilities, with on-site maintenance and tracking of failures and recoveries; we had a contractual obligation to meet a specific MTBF target).A small team was sent to the facility with me included. We were sent with a few tools including a Tektronix 1241 logic analyzer, in-circuit emulator for the microprocessor in the failing units, and a DEC minicomputer to run the cross-development toolchain for the target systems. Lab space was provided by the facility, with access to our units in the field as needed (we were provided with facility ID, and escorts as required).We found a number of problems that prove the old adage about theory and practice (in theory they're the same, in practice they're not)..1. One of the developers on the project had removed power-up ROM and RAM tests because"manufacturing test will catch them, and it will shorten the boot-up time". When we re-enabled these tests we found several units in the field that failed immediately. Some of the chips were not seated properly in their sockets (including at least one bent pin) and had not been caught in test.2. Some ribbon cables had been improperly routed and had been punctured by the pins from the back of one of the modules when the unit's lid was closed. It was assumed, but never proven, that this was shorting some signals in the cable and module. The cables had to be replaced and routed properly. How these units passed manufacturing test I'll never know.3. Around midnight one night I discovered that I could build up a pretty good static charge by walking around in the lab despite the tile floor. The air was very dry. I touched the stainless steel case of one of the units in the lab and it failed immediately. I cycled power, and it resumed operation, so I did it again. It failed again. I couldn't make it fail if the in-circuit emulator was connected, so I decided to risk the Tek 1241 (pretty expensive gear at the time), and set it up to trace the address and data buses on the unit's CPU. I discovered that one of the serial I/O chips was generating a DCD (Data Carrier Detect) loss interrupt even though the DCD- pin on the chip was grounded. The software was not correctly decoding that interrupt because "it couldn't happen". I learned later that the interrupt was caused by ground-bounce under certain conditions. I fixed the interrupt decode software, burned new EPROMs and by dawn I had upgraded the dozen or so units that had been failing most frequently. After upgrading the rest of the units the failure rate plummeted to well within our contracted MTBF.

author: KJDS
author_rank: Super Contributor
timestamp: September 05, 2013, 07:11:52 am
content: I've worked in two facillities where they'd installed very expensive anti-static flooring.The cleaners then covered, day by day, the expensive flooring with non-conductive floor polish.

author: notsob
author_rank: Frequent Contributor
timestamp: September 05, 2013, 08:41:32 am
content: Two situations from years ago (more like decades).A mainframe computer was having intermittent memory parity failures. The engineers just couldn't track the cause down. One of the engineers was taking a break, a coffee and staring out the window when he noticed that each time the mainframe failed the radar from the local airport (easily seen thru the window) was aimed in their direction.Yes that radar was the cause of the memory parity errors.Secondly, in the days of the mechanical accounting machines, a customer reported his unit was malfunctioning, with incorrect additions. This led to a very long attempt to fix the problem, which seemed random and 'unfixable'. It was eventually tracked down to the operator, a small woman, she had to lean across the accounting machine to change ledger sheets, and was hitting random keys with her breasts.So there are two real life problems that show that it's not always the equipment, but differing environmental issues can be at work.

author: madires
author_rank: Super Contributor
timestamp: September 05, 2013, 11:16:15 am
content: Quote from: Dajgoro on August 15, 2013, 05:03:09 pmWhile working for a carrier a datacenter technician managed to put an interface module upside down into a Cisco Catalyst 6500 and blew the whole chassis. That exceeded his yearly salary.

author: dfmischler
author_rank: Frequent Contributor
timestamp: September 05, 2013, 11:48:45 am
content: Quote from: madires on September 05, 2013, 11:16:15 amWas the union influence strong enough that he got to keep his job?

author: tealsuki
author_rank: Contributor
timestamp: September 05, 2013, 11:51:45 am
content: God, this is like reading a Dilbert book. I can't wait until I'm old enough to have a few D'oh stories under my belt.

author: madires
author_rank: Super Contributor
timestamp: September 05, 2013, 12:12:25 pm
content: Quote from: dfmischler on September 05, 2013, 11:48:45 amSorry, I don't know what happened to him.

author: madires
author_rank: Super Contributor
timestamp: September 05, 2013, 01:34:07 pm
content: Some more telecommunications industry fun. Long time ago when the Internet started to become common I worked for an ISP and we leased lines from several carriers. To get better/faster service in case of an outage or faster delivery for new lines we had service contracts with the carriers. The largest one (not hard to guess) had to monitor all leased lines we got from them 24x7 and in case of a line problem we should get a report every 4 hours and the final report had to state the cause of the problem. Of course we had also our own network monitoring and I can't remember a single instance the carrier's monitoring was faster in detecting problems than our own. We called them and the guy at the other end mostly said something like "Oh, you're right. The monitoring system shows an alarm for that line.". That was a service we've paid for! Back to line outages. 95% of all final reports claimed "problem vanished while debugging". We assumed it was something embarrassing they didn't want to tell us and/or trying to avoid giving discounts for selfmade problems and not meeting SLAs. But the most truthful and funniest report we got stated "outage caused by a drunken technician in the telephone switch (which also housed the network elements for leased lines) tripping over the wrong wire". Someone at the carrier must have been very mad to send such a report to a customer. We had a good laugh anyway.

author: Mr Smiley
author_rank: Frequent Contributor
timestamp: September 05, 2013, 02:12:20 pm
content: Now i can't confirm this but it was told to me by a software lecturer while doing an electronics degree back in the early 90'sIt was a lecture on software bugs and the consequences of incomplete documentation.Tests were being done on submarine torpedo guidance systems. When the torpedo was fired, it would travel away from the sub and hunt for targets within its direction of travel.The software had a built in safety system such that, if for any reason the torpedo turned by 180' and headed back to it's destination, it would self detonate, simple enough. But apparently the crew of the sub were not informed.One day during tests, the torpedo was left stuck in the firing tube and had already self armed.The sub turned round to return to base.The lecturer said all were killed.The morrow of this story is that users should be notified of all software protocols and safety features.As i say, i can't confirm this is true but was one of many examples of all parties not knowing what the software really does.

author: Towger
author_rank: Super Contributor
timestamp: September 05, 2013, 03:12:38 pm
content: Quote from: notsob on September 05, 2013, 08:41:32 amI heard the very same story (except she was a large woman) from the person who as a young lad was sent to watch the machines, and had to inform her boss the cause of the problems. Was this Burroughs in Ireland or were well endowed women a world wide threat to comptometers?

author: Galenbo
author_rank: Super Contributor
timestamp: September 05, 2013, 08:26:55 pm
content: I worked on a dual 1MVA redundant rotative 11kV UPS.Some safety report said there was no physical isolation between both units on a certain spot, so an unpenetrable shield has to be installed.Guess what: the least expensive company got the contract. Net even everybody understood central european languages, nobody understood the difference between Voltage and Current.After their job, everybody got to a distance, my collegue started the machine, with a huge fire as result.Some yelling was going on between their "boss" and his "workers" to determine the cause of this.Then, one of them said loudly:I swear I didn't drill in that red cable.Even before anybody dared to go close to the machine, even before anybody saw it was the red 11kV cable producing fire, with a hole in the insulation as the cause :-)

author: dfmischler
author_rank: Frequent Contributor
timestamp: September 05, 2013, 09:13:24 pm
content: One day on a customer site near Tampa the lights suddenly went out and the emergency lighting came on as everything critical in the whole building went on UPS, and we heard the generators start up (fortunately, it all worked). We went outside and discovered that a guard rail crew down the street had just used their hydraulic post driver to push a steel post through the underground 4.8kV power line that fed the whole neighborhood. I don't know why they didn't think they needed to get the underground utility marking people out before starting

author: warp_foo
author_rank: Unknown
timestamp: September 05, 2013, 10:26:13 pm
content: Quote from: madires on September 05, 2013, 11:16:15 amA few years back I worked in a 65,000 ft² datacenter. We supported about 3000 windows servers, 1200 Unix, and the odd mainframe here and there. For some reason HQ decided it was time to audit the infrastructure and see what upgrades were required. The results for the network group were ... interesting.There was somewhere in the neighborhood of 40 - 50 Catalyst 6500s:1. Of the ones with dual power supplies, each supply was rated for 120v service.2. At least half only had one power supply rated for 240v.So, none of the C6500s with dual supplies would continue with a failed PDU leg or a PS outage as the C6500 required dual 240v supplies for redundancy.The ones with only one PS? Well, they were purchased with two, but the network manager decided to remove the second supply and keep them in the spares locker in case a PS failed. That way they'd have a spare handy...I'd like to point that every switch had dual supervisor modules to fully support redundancy.ETA:Same data center, different problem.I had a minor cable swap to perform on a Saturday morning. Move one multi-mode fibre from one patch panel to a second patch panel. If any of you have ever been in a full-on data center, in normal operation they are quite loud. Loud enough that normal conversation just isn't possible.Imagine my surprise when I get in that morning and the data center is dark... and silent.Apparently, one leg of electrical systems was undergoing a firmware upgrade to the Liebert PDUs. At this particular data center there are multiple PDUs per zone, and - of course - we wre running the PDUs at close to 80% load. At some point during the upgrade the technician either zigged or zagged improperly, so the firmware upgrade was unsuccessful. After powering the system back 'on', the tech packed up and moved on to the next stage of the upgrade.Rather impressively, the battery backup system (an large room with rack after rack of deep discharge lead-acid batteries...) lasted about 30 minutes, the alarm went off, and roughly one third of the data center lost power.My third, unfortunately.To rub salt in the wound...A few weeks previous, one of the PHBs decided that all of the server keys should be securely locked in his desk drawer. At that time, Sun servers came with a key to lockout the ability to power cycle the machine. Most places usually just turned the key to the run position and left them in the keyslot. When it comes time for the electrician to bring the power back up, he tells us that we have to key off all of the affected servers to avoid the in-rush power draw of 600-odd Sun servers trying to post all at once. (The vast majority being E450s, E4500s, and E6500s)I believe that we eventually had security 'break' into his office and desk so we could get the keys.My five minute job turned into 8 hours.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: September 06, 2013, 12:06:53 am
content: Not an engineering stuff up story, but an industry story all the same.Out of school I got an Engineering cadetship with the local water-sewerage authority.I worked at a sewerage treatment plant which was spread over many hectares. Everyday we were paid an extra dollar because of the smell. Which after a while didn't really worry anyway.To get around our site we walked, quite long distances, and sometimes I used to take a short cut, along the walls between the incoming sewerage overflow tanks.The walls of these tanks were only about 20cm wide and about 50 metres long. They were like deep olympic pools full of swiring browny grey bubbling fluid. Tampons, condoms, turds, branches patrolled the surface and who knows what creatures, diseases lurked beneath.The point being, that travelling this path wasn't without consequences.Anyway my Boss saw me walking across between the tanks one day and he pointed out the OH&S issues involved.Ok, Ok. Yeah boss, I wont do it again.But then in a change of mind he said he would give me a race across the tanks, this was possible as there were 3 tanks and two indentical retaining walls. The bet was a schooner. (0.425 litres of beer).Ready set go.And we're both walking carefully along our walls, I look up and see that he's walking faster, so I speed up. He's jogging, so I jog faster. He's running and so I'm sprinting with my arms out wide ready to try to catch the wall if I slip.Anyway I won and got my beer but I'm not entirely sure it was worth the risk.

author: IanB
author_rank: Super Contributor
timestamp: September 06, 2013, 12:23:58 am
content: As a chemical engineer I can certainly vouch for the fact that all sorts of interesting events and circumstances can be encountered while working on a plant site.One of the simplest of these is found in the open steel stairs and walkways that are used to access the upper levels of a plant, often very high above ground level. It's not for anyone with a fear of heights since there is no solid floor beneath your feet, just an open grid that you can see right through. I don't have a particular problem with heights, but I always get a touch of vertigo when I am "walking on air" dozens of feet above the ground.

author: madires
author_rank: Super Contributor
timestamp: September 06, 2013, 01:44:48 pm
content: Quote from: warp_foo on September 05, 2013, 10:26:13 pmUnfortunately most network elements don't support mixing different PSU types. In some cases it would be very helpful, for example if you only got one AC line but could get a -48V DC line (battery buffered) too.QuoteOuch! Redundancy for/by morons :-)QuoteSince power problems cause mostly larger outages having dumb PDUs might be not a bad idea :-) Our standard design was to have two DC paths and 3-phase AC for all cabinets.I could tell tons of stories about IP routing but I think it would become too off topic and boring for most readers.

author: dfmischler
author_rank: Frequent Contributor
timestamp: September 07, 2013, 08:09:13 pm
content: I guess this is more of a programmer joke. One place I worked, I remember being told that the lab was going to be inventoried. Every resistor and diode. The labor to track that kind of thing probably costs more than the parts. Of course, I have no problem with them tracking the test equipment, etc. We had a cabinet with little drawers that was labeled for common components and their values. Two adjacent drawers were unused and unlabeled, but had a bunch of small, manila envelopes in them. So I decided to label them. I labeled one of them, "Bits, 0", and the other, "Bits, 1". It was fun to see the inventory crew come in and say, "You're out of bits." And we answered, "No, you can't see them." They asked, "How many are there?" And of course we said, "As many as we need. And they don't cost anything." It took them a few minutes to decide not to worry about them.

author: JackOfVA
author_rank: Unknown
timestamp: September 08, 2013, 01:17:00 am
content: My business is developing and selling various devices to my fellow amateur radio operators. Most of my products are available as either kits or assembled and all the kits are provided with extensive step-by-step instruction manuals with many photographs and construction checks.One particular product has a printed circuit board that's perhaps 3.5 inches x 2.25 inches and has around 75 or 80 surface mount parts. All the resistors and capacitors are 1206 or larger and it's not a difficult board to assemble with a halfway decent soldering iron and small diameter solder. The parts are cut from tape reels mostly and go into plastic or paper envelopes. Ceramic capacitors are identified by separate envelopes since they have no other ID.Received an E-mail from a purchaser of this particular product informing me that he had problems after assembly - didn't work at all. I asked him to return it to me for study and repair. I opened up the weatherproof enclosure housing the PCB and found the following ...1) All the surface mount resistors were installed upside down, i.e., with the value marked surface against the PCB and the white ceramic layer visible. Needless to say, this made verifying the correct parts were installed at each location difficult.2) Parts that were in cut plastic tape (some inductors and small electrolytic caps) were not removed from the tape but rather the tape was melted to the PCB as his way of attaching those parts to the PCB.3) The rest of the soldering looked like it might have been done with a 250 watt iron suitable for working on the gutters.I told him that the board was not salvageable and offered him another kit at half-price provided he used someone else (who I identified) to assemble it for him and that he would have to make suitable payment to the assembler. I also sent the screwed up board to the assembler and he took it on as a challenge, removed all the parts and rebuilt it from the bare PCB and eventually made it work. Took him a long day to do it, though.

author: Shock
author_rank: Super Contributor
timestamp: September 08, 2013, 09:23:22 am
content: In a former job had a customer call up for a warranty and demanded a repair within a day returned to them. They explained they had been trying to get a repair with some 3rd party for weeks and was sick of waiting.So explained what we did and that I could guarantee repaired or replaced, 5 days total turnaround including postage. Which meant an actual 1 day turnaround for the inspection and repair our end.They got really abusive, the most I have ever heard someone get, a real scumbag. I took it all and at the end explained that's all I can do. They had someone in the background encouraging "to teach me a lesson" etc. In the end after getting no further they decided with a few more expletives thrown in to hang up.I had notes of the all their details and the serial etc. As soon as I got off the phone I told everyone in the company to stonewall them. No soup for you! That means no repaired soup, replacement soup, or even new soup if your business needs soup to run.Free lessons, no deposit required, come and get em.

author: woodchips
author_rank: Frequent Contributor
timestamp: September 11, 2013, 10:19:29 am
content: Nearly a whole day to discover why an RS232 link didn't work, two wires, no ground.Couldn't connect an old Apple 2 to a robot control, characters corrupting after the first 4 or 5. The Apple doesn't use a crystal for the baud rate, one stop bit means the characters slip slightly and then corrupt. Always use 2 stop bits!Using RS422 around a newspaper printing works at 10Mbs. Errors, oh just swap the two differential wires over and it goes away, until the next time.Don't, whatever you do design 100A PSUs with copper busbars inside that are just screwed together with a couple of M3 screws. All internal screws must use those slightly dished, Belville?, and serrated washers, they are the ONLY ones I have found to actually stay tight for years.Installing a Strowger telephone exchange and leaving all the regeneraters off home position after testing waiting for the suite fuse to be installed. Four racks, five shelves per rack, 10 per shelf, 1A per regenerater coil equals a very large spark! Bit mean really.

author: TerraHertz
author_rank: Super Contributor
timestamp: September 11, 2013, 01:01:56 pm
content: One time I was working in a group of engineers, building an experimental 'ink jet printer'. Well, sort of. It was supposed to continuous print onto huge rolls of cloth. And the intention was to be able to do expensive cloth, like silk, so there was a very high need to not make ink blots. The work was being done in a small company in Sydney, that happened to have bought some early inkjet patents from the CSIRO. And so a Japanese textiles company was partnering with them. Pity the two Japanese engineers who got sent to Sydney, to stay until project completion. I always thought they must have done something terrible back home, to have been sentenced to that. But they were great guys. Really didn't deserve the mess they found themselves in.Because... the Australian company's R&D dept head (and my boss) was a nutcase Frenchman. There were numerous different modules to be designed and built. The Japanese got allocated some, I got some, and the Frenchman decided he'd do the 'really hard one'.There's a lot of data to be streamed, when you're trying to inkjet print a meters-wide bolt of cloth that's whizzing past at high speed. The 'print head' didn't move, it was the width of the cloth. Anyway, the 'master processor' was some AMD bit-slice thing (I forget the number) and the Frenchman took that on. It was to be a stack of three PCBs, each over a foot square, plugged together with ... ah, my memory is shot tonight. Those white connectors with three rows of pins. Euro..something?Anyway, we were all busy with our bits of stuff, CAD-ing away. Normally I'd prefer to do mutual design reviews to catch as many errors as possible, but Frenchman was a paranoid secretive kind of guy, and it was a rush. So no reviews of anyone's designs. He got to the point of having prepared the gerber files to be sent out to have his boards done. And then he had a brilliant idea.Did I mention he was secretive? Paranoid? Well despite that this was all a 1st prototype (to print on cloth FFS) he felt that his design was so special he should do something to stop anyone being able to reverse engineer it. OK, three big, dense four layer boards, power and ground inner planes, tracks on outside. How do you obscure the tracks?Simple! (He figured.) Just swap the layers around. Put the power planes on the outside, tracks inside. It will all still connect the same. Just re-label the gerber files.Can you see where this is going?He didn't tell anyone about his brilliant idea. After all, he's the R&D department head, why should he?He sent the gerbers out. The boards came back. They looked quite pretty - all that solid copper plane on both sides. With the.... round clearance holes around plated-through holes. And.... no pads at all, anywhere!Because there _are_ no pads on inner layers. The solder masks were OK, but no copper around the holes.Ha ha ha... the rest of us didn't like him at all, and only stifled guffaws because he was the boss.There wasn't time to do another PCB run. So he had to make them work.The first thing he did was a bare-board power test. Sure enough, +5 and GND were shorted. (This is what can happen when you don't do a board sanity check, by stripping netlist from the board layout in the CAD program, rebuilding a netlist from the copper, then comparing the two netlists. No, he didn't.)How do you find a power rails short INSIDE a bare four layer board in which the surface layers are solid copper?It would have been more fun to let him crash and burn, but we did need to (try to) get the project done. So I offered a solution. I have an arc welder. Soldered straps to the surface layers, pulse welder power to them. One small spot inside the PCB goes 'pop'. Thats where the short was. On other boards (we had 3 sets) excavate with Dremel & fix it neatly.Then it was great fun watching him trying to get solder to go into the tiny holes with IC legs sticking through them. (This was before surface-mount.) Eventually he got all the pins soldered.There followed several days of him being mystified by severe failure of the board stack to do anything sensible.And then the penny dropped. He'd drawn the schematic as multiple sheets (of course), but he'd forgotten to correctly port most of the major buses from sheet to sheet. Then auto-routed the boards.Result: lots of things that should have been wired through the connectors between the boards, weren't.This was a real shame, since everything else all the rest of us had done worked as planned. So the Frenchman's egotistical stupidity was pretty much the sole cause of the project not succeeding.There was an amusing thing that happened with one of the components I did. It was a data stream manager, with an Analog Devices AD2100 RISC processor, on a two PCB stack. Mainly it was just a big FIFO, but then had to split the data flow and allocate segments to head driver boards. It had a program memory space that was fast RAM (not DRAM), externally loadable. As always on any processor I did, I included a watchdog reset circuit. I'm used to using a pretty simple one - the CPU has to keep pulsing an IO bit in something close to a valid mark-space ratio (but fairly slowly, so it has plenty of time to do other things), or it gets a reset pulse. There's also a status LED on Reset. So you can see if the CPU is being reset. Repeatedly, if it can't start right.So I got the PCBs back, populated them. No software ready yet, but powerup should still produce the reset LED pulsing effect.Turned the board on. The LED turned on, blinked a few times then went out. Huh? Try again. Same effect. It would pulse a few times, then stay off. Somehow the watchdog circuit was being correctly told to hold off. But there's no code... how? What?Ah, but there _is_ code! The RAM is full of junk on power up. And the CPU can write to its address space too. Every time the CPU was reset it would start executing at one end of RAM, and just run junk data. Which also meant it would be modifying that junk. It was quite a fast CPU. It had a few hundred milliseconds to come up with some combination of modified junk code that was a) stable, and b) did something more or less correct to the watchdog circuit. If it didn't, it would get reset - which made it re-run different junk, changing more random stuff.So it was a kind of primitive demonstration of digital evolution. Pat the watchdog right, or die (and be reincarnated to try again.)This meant that even with code loaded, I couldn't trust the system to reset if the code crashed - if there was any junk code anywhere in the address space.The solution was to make sure that all the unused codespace RAM got loaded with NOPs, with a final jump to the reset entry point.Oh, and that two-board AD2100 system worked first time. Once we put some code in it.

author: grumpydoc
author_rank: Super Contributor
timestamp: September 11, 2013, 03:26:42 pm
content: QuoteI once got called to a client site to fix an RS232 link which the on-site "techs" couldn't get going.After a quick look my recommended action was:1 - re-install the null modem which someone had removed.and2 - try running both ends at the same baud rate.

author: jeroen74
author_rank: Frequent Contributor
timestamp: September 11, 2013, 06:31:11 pm
content: QuoteDIN41612 perhaps?

author: SeanB
author_rank: Super Contributor
timestamp: September 11, 2013, 06:57:24 pm
content: Today...... why is this message coming up on the login screen? Tell them to press Caps lock off. They press num lock. I might have been a little aggressive there.......

author: bookaboo
author_rank: Frequent Contributor
timestamp: September 11, 2013, 09:19:28 pm
content: Haha, reminds me of getting a phone call from the bosses wife who was standing in at reception for a couple of hours one day. "Can you come down here, I can't get the PC password to work I think the keyboard is broken"Went down and she showed me that no matter what she typed it just came up as *********.

author: notsob
author_rank: Frequent Contributor
timestamp: September 11, 2013, 10:04:03 pm
content: Or being told a 5 1/4" floppy disc wouldn't work, only to find that it had been labelled by putting it into a typewriter to write on the label.

author: dfmischler
author_rank: Frequent Contributor
timestamp: October 13, 2013, 05:37:18 pm
content: I don't have a date for this, but it must have been in the very early 90's. I had a group of software guys and we had a customer deliverable project to do on a MicroVAX and a bunch of terminal servers in a DEChub 90 backplane. This thing provided a way to connect a bunch of small terminal servers and/or a workgroup bridge into a fairly small space without needing lots of separate ethernet cables. But it didn't have a 10baseT port, or an AUI connector, so you could only connect it up to thinwire ethernet (aka 10base2, the one that used RG-58 type cable with BNCs). The building already had a fair amount of 10baseT and some thinwire ethernet in the server room. So I waited until most people cleared out after 5, got out a spool of Belden 89907, a ladder, BNCs, crimper, etc., and started running cable from the main server room to my group's area. When I was almost finished (stripping back cable for the BNC on the MicroVAX end), a manager from Corporate saw me, and said, "Don't you have technicians who can do that for you?" I said, "I asked them, but they say they won't do it because they don't have the training." He asked, "Have you been trained for that?" I said, "No, but my group needs it." He walked away, but I later found out he told the head of the division, and put a real nice letter in my employee file.

author: Dave Turner
author_rank: Frequent Contributor
timestamp: November 12, 2013, 12:41:45 am
content: Back in the days of mainframes when they were leased as opposed to bought and an increase in "processor" speed could be purchased at an exorbitant price (engineer to be sent to site to remove a link thus doubling the clock speed) one particular site reported a serious cascade failure of their disk packs.There will be those who remember mainframe clean rooms and the associated interchangeable sealed units where a human hair could be pushed out of the way by the 'flying heads' but a particle of smoke could literally cause a disk crash.Imagine the scenario- contaminated disk pack loaded into the reader - disk crashed - oh dear there is a problem with the reader - lets try the disk pack in another reader - eerk - oops maybe its the disk pack - never mind I have a copy on another disk pack I'll try reader one again - aagh - etc. Yes this did happen as gleefully related to me by an engineer involved in sorting the issue out.Fast forward fifteen years - standalone PCs are introduced into the work place at approximately 1 per 4 personnel to solve all problems (note 5 1/4" floppies) - my superior carries his coffee in the same hand as his disks - splash - dead disk drive - oh well try another PC - oops - etcetera.25 years on; what's the latest equivalent? Dilbert where are you when we need you?

author: dfmischler
author_rank: Frequent Contributor
timestamp: November 12, 2013, 01:54:58 am
content: Quote from: Dave Turner on November 12, 2013, 12:41:45 amI think it goes, "Damn, this PC is acting like it has a malware problem, too. I'll try my website with that PC over there instead."

author: GreyWoolfe
author_rank: Unknown
timestamp: November 12, 2013, 05:03:57 am
content: My story is not industry relevant but does show that "the customer is always right" is often taken to the extreme. I worked for Sears in the mid 90's selling lawn equipment. I mower was sold and the customer brought it back a couple of hours later saying it didn't work. My manager asked me to look at it and when I did, I found a hole in the side of the engine block. I checked and there wasn't a drop of oil in the machine. I told the customer that the mower had been started with no oil in it and we would not be able to do anything about it. He made a loud enough noise and the manager replaced the mower. My boss did tell me that I handled the customer properly but in the grand scheme of things, the cost of one mower to make a customer who was obviously wrong, happy was insignificant. I guess it did turn out to be significant as K-Mart bought out Sears. K-Mart? Enough said on that. I now work as a field service tech servicing equipment for a state agency and that alone is worth a book. Think Bill Engval-Here's your sign.Tom, NW0LF

author: johansen
author_rank: Super Contributor
timestamp: November 12, 2013, 07:06:06 am
content: only somewhat EE material; some friends of mine lived down the road a mile, walked over to my house one day, wanted to know how to put in a push button start into a pickup.I walk them through what's going on, asking cryptic questions so as not to make them feel retarded...I discover they wired up the 4 AWG battery wire to the pushbutton.. didn't know what the solenoid on the starter is for.yes, that's gossip and i managed to post at 06:06:06. lmao.

author: GreyWoolfe
author_rank: Unknown
timestamp: November 12, 2013, 12:43:39 pm
content: I just remembered another story. Another tech and I were in Georgia for training as back up technicians for south Georgia and as part of our training, we went to some of the sites to see how all the equipment worked together. We both noticed that the sites had bypassed the safety interlock on the card printers and were operating the printers with the cover open. We both commented to ourselves that that was an accident waiting to happen. When we brought it up later, we were told to ignore it, the techs tried to correct the behavior and had no success so they were leaving the sites to operate that way. On the morning of the last day, a great hububb ensued and one of the trainers left in a hurry with a printer. We found out that someone put their hand where it didn't belong while the printer was printing and had the tip of a finger removed. The printer was fine, but had to be exchanged out and brought back in to have all the blood cleaned out. I was happy to be getting ready to head back home and not be the one to clean that printer out. In the course of my being the backup tech for about 2 years, when I went up to Georgia to run service calls, I still found sites operating with the printer cover open. Obviously, one examiner's painful lesson was not learned by everyone else.Tom, NW0LF

author: vk6zgo
author_rank: Super Contributor
timestamp: November 12, 2013, 04:08:45 pm
content: Back in the day,the various manned TV Transmitting Stations in the Network I worked in were given Telex Machines & tape reperforators.We were supposed to send in weekly reports,as well as separate ones for faults.At the Tx site I worked at,we made up "cheater" tapes with the different addresses & headings,etc required,so we didn't have to type all that stuff in each time.We ran them when we made up a new tape,inserting the current information as required.These lay around on the Telex desk & looked a bit untidy.I came in one day to start a 7 day afternoon shift,& the morning shift bloke complained:-"I can't get this tape to read ,looks like the reperf is faulty"" Have you tried the others?"I replied,then noticed they weren't on the desk.Looking up,I saw they were all attached neatly to the Notice board with drawing pins.Mucho fun fitting tape over the extra holes,especially,as the culprit had apparently had several "goes" before he got a neat enough job,resulting in multiple holes.We then had to run all the tapes through & make new ones,as the Boss would have yelled.Nobody ever owned up to this bit of lunacy!

author: Dave Turner
author_rank: Frequent Contributor
timestamp: November 13, 2013, 12:43:29 am
content: Nothing changes. 5 1/4 inch floppies stapled in with file folders so they didn't get lost! I've also seen that happen with 3 1/2 floppies. What happens with USB sticks, SD cards etc. I shudder to think.

author: tealsuki
author_rank: Contributor
timestamp: November 13, 2013, 04:24:34 pm
content: Quote from: Dave Turner on November 13, 2013, 12:43:29 amMust be one HECK of a stapler!

author: SeanB
author_rank: Super Contributor
timestamp: November 13, 2013, 07:08:37 pm
content: Parcel stapler will go through the cases no problem. It will punch a staple through 6 layers of plastic laminate with ease. the bigger box staplers will do it as well, but will leave 2 slits where the jaws slice through to close the legs underneath.

author: Dave Turner
author_rank: Frequent Contributor
timestamp: November 13, 2013, 09:39:25 pm
content: A good office stapler, designed for more than just a few sheets of paper, will go through a 3 1/2" floppy.

author: dfmischler
author_rank: Frequent Contributor
timestamp: December 08, 2013, 04:15:37 pm
content: In the mid 80's I worked for a company that used a lot of Gates cells (early sealed lead-acid cells that looked just likethese) to hold memory during power failures, etc. For some reason the proverbial shit-load* of these cells was delivered to our site, even though final assembly was going to take place in a plant we owned three states away. The stock room morons decided that they could pack the cells tighter into storage if they removed them from the factory packaging. So they did. Everything went OK until they got to the second layer (note the uninsulated terminals on top of the cell; you can't see the shiny metal bottom in the picture). Amazingly, the stock room people started smelling smoke while they were innocently stacking the batteries, but they kept going until they noticed actual heat. As I recall, they emptied several dry chemical (A-B-C) fire extinguishers at the stack of batteries, without much effect. The fire department had the good sense to knock the stack over with a long-handled tool before finishing the stock room off with water (to eliminate possible secondary fires). I have no idea what that fiasco cost our insurance company.*I never fully understood the term "shit-load" until I moved to farming country and discovered that the typical small family dairy farm had a 300-500 bushel manure spreader. The folks who know say that medium fresh cow manure weighs about 1.6 tons (1450 kg) per 100 bushels.

author: SeanB
author_rank: Super Contributor
timestamp: December 08, 2013, 05:30:41 pm
content: I see you met the cousins of some I knew then....I rejected some capacitors as they failed incoming test for both capacitance and ESR. Seeing as they were the same age and batch as the ones in use that were failing the testing was good to do on them. 1 month later they were back, saying they had passed visual inspection perfectly. I then cut the leads off flush with the bodies ( difficult to do with a wet slug tantalum capacitor with a positive leadout made from tantalum wire that extended 2cm from the seal) and returned them with a polite note that they still failed ELECTRICAL parameter testing.I got a list then that came in on a pallet with a fork lift truck, containing books equal to any phone book with a listing from stores sorted by the word "cap", printed on A4 paper double sided in fine print, and spent a month reading page after page consisting mostly of the manufacturers part no, a ref number, a store location and a description of " Capacitor, Await Data". Those were only usable if the manufacturers part no was readable as a value, or there were a few thousand and I wanted to take a gamble on them. Still have a few 100uF 6V electrolytics that are 20mm dia and 80mm long. I thought the dimensions were wrong, but no. Luckily I found a lot of 100uf 10V units that were new, so ordered a lot. Smaller and could fit.

author: johansen
author_rank: Super Contributor
timestamp: December 16, 2013, 01:46:02 am
content: Quote from: dfmischler on December 08, 2013, 04:15:37 pmlol, digikey.. i can buy a 12 volt 5 ah cell for 15$.another story about those cells: i worked for an organization that had a large number of of 2 volt 2 ah cyclon cells, 24 batteries per tray, 18 trays.. arranged in series-parallel for 288 volts nominal.Only one problem: the nickel tabs were bent over and spot welded to the next battery, 24 batteries in a tray, shrinkwrapped as one brick.....Well, guess where the sulphuric acid vapor goes?I can hear a noob saying "but they are sealed cells!!!!"And since there's a black plastic sheet over the clear shrink wrap on the terminal side.. no one could inspect for partly corroded terminalsso when there's a 20? amp load test every time the bench starts up (10 minutes was about all the battery was good for), and the nickel plated copper terminal opens, and the entire battery goes up in flames...here's a photo of the test bench:http://media.defenceindustrydaily.com/images/ELEC_CASS_Hybrid_Testing_System_lg.jpgthe battery compartment is left most compartment, center, with a black handle on the removable cover.. it has 6 vent holes, about a half inch diameter, for about 2 cubic feet of batteries.i do recall a story about a battery fire.. the bench operators just sat back and watched it burn lol.that cass hybrid test station was probably one of the navy's bigger boondoggles, they spent i would estimate at least 2-3 billion dollars on about 680 of those benches over 20 years. but i'm not sure there was any other way to do it, as there are ten thousands of unique electrical devices that had to be fixed down to the component level.. across many generations of technology..

author: Excavatoree
author_rank: Frequent Contributor
timestamp: January 02, 2014, 01:38:42 pm
content: Dave's oscilloscope troubleshooting reminds me of a common problem we have with our service people. A machine is built, and the latest software is installed. If there is a software problem, most often it is caught during factory testing. Rarely, there is some obscure bug that only shows up once some units are in the field. When that happens, the problem exists on more than one machine. This seems logical, but our service people don't grasp this.A machine will fail, years after it was built and working normally. The service person will more often than not ask "what software is on it?" If, by chance, there was a revision since the machine was made, the service people will scream and holler "we need the new software for this machine!" Instead of finding the real problem.If our guys were working on Dave's scope, they would want to re-flash the latest firmware first thing. I suspect they are buying time while they figure out what the real problem is - telling the customer "Those darn engineers won't get us the right software!"

author: Tinkerer
author_rank: Frequent Contributor
timestamp: January 03, 2014, 03:49:38 am
content: I am currently working as a testing tech at a certain company(before I move to an actual EE position in a few months). Only been there a couple months now and already got at least one story.(among many little ones; to one of the EEs there from a boss guy: "what?! you left that full roll of solder out without its packaging?! get rid of it, we cant verify the date on it")So, most of the devices that come through are required to go on burn-in for 48 hours. There are procedures to follow for everything and this particular device was no different. On this particular device, you connect power and then connect one of the 8 ethernet ports to a test fixture so data can be constantly sent back and forth. Notice how I said one of the eight ports? Well along the way, someone forgot that if you are really going to burn something in, you need to test the entire device, not 1/8 of the device. Apparently there is also no test fixture for actually testing the entire thing at once over those 48 hours; and there is only a single test fixture for testing a single port, period. The Methods supervisor guy(who basically does quality control type stuff and is the guy who didnt like that solder) was quite perplexed as to why all this was when I brought it up and as to how all the previous devices that had come through had even been burned in properly. Needless to say, I then ended up with 4 of these sitting on my shelf that I couldnt do anything with until they wrote up the proper procedures for them. hahI had come in to replace a previous guy who was leaving. The way he did things was bit odd though and he let alot of stuff slide. Hence why things went unnoticed.I have to hand it to the people at this particular company because they are actually trying to improve things and from what I hear, it was alot more chaotic in the past. This included a large metal cabinet that ended up stuffed full of products that failed in some way because no one wanted to deal with them. That actually got cleaned up.

author: Kohanbash
author_rank: Regular Contributor
timestamp: January 03, 2014, 05:08:05 am
content: Quote from: liquibyte on August 15, 2013, 10:26:17 pmThis is often done intentionally so that a lamp can be connected to the outlet and be controlled by the switch.

author: KJDS
author_rank: Super Contributor
timestamp: January 03, 2014, 09:50:17 am
content: Quote from: Tinkerer on January 03, 2014, 03:49:38 amOne place I worked had a raised floor. Just before one audit about $1m of non-conforming product was hidden underneath it.

author: AndyC_772
author_rank: Super Contributor
timestamp: January 03, 2014, 10:03:17 am
content: Quote from: Tinkerer on January 03, 2014, 03:49:38 amVery common, and for a simple, good, reason.Non-trivial faults require expertise and detailed knowledge of how the product works in order to fix them. More often than not, that knowledge resides in the brains of the R&D dept, and nowhere else. The simple truth is:[Cost of failed equipment] < [value of sales of the new equipment which R&D can design when they're not fixing boards]Writing service manuals, test procedures, test software, developing test fixtures and so on is *enormously* time consuming, and it's amazing how few people outside of R&D really understand this or its implications. That's why test processes so often allow finished goods to be sorted into "good" (ie. working, shippable) and "bad" piles, but don't go into any more detail. The total cost of the "bad" pile rarely justifies diverting the attention of the only people able to fix it.

author: bookaboo
author_rank: Frequent Contributor
timestamp: January 03, 2014, 11:23:04 am
content: QuoteI can just picture someone taking apart the socket to inspect the "fault", verifying no voltage present then switching on the light to help themselves see.Hey presto a nice shock awaits.

author: Kohanbash
author_rank: Regular Contributor
timestamp: January 03, 2014, 02:22:34 pm
content: A couple of years ago we got a new PhD who needed to run some tests to characterize a motor. After offering to prepare the cable harness's for him he insisted that he was an EE and could do it on his own.The next day he comes to me and says that there is something wrong with the motor or its controller if I can take a look at it. Sure enough I go take a look at it and the cable harnesses were all wrong. When I mentioned that they needed to be re-made he quickly grabbed the large cutters on the bench and cut through the motor power and encoder wires at the same time without turning off the power.Sure enough the motor, the encoder, and the feedback pins on the controller all got fried.

author: KJDS
author_rank: Super Contributor
timestamp: January 03, 2014, 05:45:37 pm
content: Quote from: AndyC_772 on January 03, 2014, 10:03:17 amOne of my huge bugbears is that many engineers don't spend anywhere near as much time on the production line as they should. There are some times when a small failure rate is acceptable. Complex but cheap products, such as cellphones are an example. It often is acceptable to live with a 2% failure rate. Most low and medium volume products often don't have anywhere near as much design time spent on them to iron out all the issues. The product starts on the production line, design sorts out a couple of issues in the first batch and then it's left to run. The next batch has a 2% failure rate and everyone is happy. The design team starts its next project and the next batch has a 5% failure rate. Production blames design and vice versa but no action is taken apart from accountants reluctantly writing off the failed units. The next batch has a 15% failure rate. Someone from production fires a silver bullet and a few get fixed and design gets blamed. A designer who wants to be doing something new is dragged onto the line, makes up a mod scheme and a few more get fixed. he works late, gets units working and is given a free pizza as a reward for working late. The following day he's back on the design of a new product and production continues.No-one temperature tests the new mod scheme and three weeks later 2000 units need recalling from the field as so many are having issues. This time design are forced to put people on the job to fix it properly eventually a new mod scheme is properly tested and implemented but this also has to cover the 100,000 poor ESR caps that purchasing bought because they were cheaper and no-one will authorize the cost of scrapping them. In the meantime, customers are buying products from elsewhere and cancelling orders all because design and production weren't working properly in the early phases of production.In another company, a process gets improved properly so that the yield is improved. This allows a better spec to be published and they can attract a price premium and more customers who want the better performance. The new process allows their next design to be better still which takes even more customers from the first company. Their volumes are now much higher and so costs fall whilst the first company suffers the opposite.It's a basic short sighted management issue. Get a production line working properly and then design within its capabilities or accept that a new process will need to be designed. I've spent time working in places where production capability is properly quantified and production has enough skill to ensure that the process is kept in control so very little design input is needed.I've also spent a lot of time eating free pizza late at night.No-one

author: liquibyte
author_rank: Frequent Contributor
timestamp: January 03, 2014, 08:53:42 pm
content: Quote from: sdk32285 on January 03, 2014, 05:08:05 amIn no, way, shape or form should plugging something in a wall outlet and switching on that same plugged in device turn on something else in a house wiring circuit, ever. Picture this. Plug in vacuum, turn on vacuum, nothing happens. Think outlet is controlled by switch, turn on switch, nothing happens. Remember that vacuum is still off, turn on vacuum, overhead light comes on. Please, tell me how this is by design. Are you saying that they designed this outlet wiring so that turning on one light plugged into it also turns on another light that's directly wired to the circuit?

author: Unknown
author_rank: Unknown
timestamp: January 03, 2014, 08:59:14 pm
content: Quote from: liquibyte on January 03, 2014, 08:53:42 pmTBF, your original post was a little unclear. I doubt many people took the correct sequence of events from it without having to read the above and your original post several times.

author: CSmith
author_rank: Unknown
timestamp: January 03, 2014, 09:06:10 pm
content: Quote from: liquibyte on January 03, 2014, 08:53:42 pmI've seen this sort of behavior in AC electrical wiring when the neutral (groundish) leg of a branch circuit is loose or has become disconnected back at the source. One device is on the L1 phase with another on the L2 phase, and only if both devices are turned on is a circuit completed between L1 and L2 with the dangling neutral now becoming a voltage divider tap. The voltage imbalance in that inadvertent divider can be significant enough to pop the overvolted load. At a minimum it is erratic.

author: Kohanbash
author_rank: Regular Contributor
timestamp: January 03, 2014, 09:30:54 pm
content: Quote from: liquibyte on January 03, 2014, 08:53:42 pmHiI misunderstood your original post. I thought that when you hit the switch they both turned on. I did not realize that it was separate steps.

author: Excavatoree
author_rank: Frequent Contributor
timestamp: January 03, 2014, 09:34:45 pm
content: Quote from: CSmith on January 03, 2014, 09:06:10 pmI didn't consider this. I thought that while someone had "series connection" on the brain, he connected the outlet in series with the ceiling bulb then in series with the switch, instead of wiring the ceiling socket in parallel with the outlet.Do electricians do a basic performance test, or does the first occupant get to do that?I once rented a new apartment. The receptacles in two of the three bathrooms didn't work. There was too much wire stripped in one of them, and it was shorting against the neutral wire. However, the receptacle in the working (first) bathroom was a GFCI, ans was wired "backward," so it worked, but it didn't pass the power to the others. (it's common to use one GFCI receptacle on a run to all bathrooms.) Of course, this is what I found first - I corrected that, then the breaker tripped, and I found the short. Still, it was better than waiting for the maintence company to figure it out.

author: liquibyte
author_rank: Frequent Contributor
timestamp: January 03, 2014, 09:40:37 pm
content: Yeah, sorry. I re-read my first post and it wasn't really very clear. I don't think the situation was in any way dangerous, just very wrong on a new house construction level. I get the feeling, in Florida at least, that the testing is up to the first occupant.

author: Unknown
author_rank: Unknown
timestamp: January 03, 2014, 09:45:00 pm
content: Quote from: Excavatoree on January 03, 2014, 09:34:45 pmUsually you find that the semi-skilled yoghurt doing the testing doesn't really understand what a test is for so they adjust the test routine as they go and then just tick all the boxes assuming that it's probably supposed to do that. Either that, or they are mentally disabled.

author: CSmith
author_rank: Unknown
timestamp: January 03, 2014, 09:56:42 pm
content: Quote from: Excavatoree on January 03, 2014, 09:34:45 pmI suspect what happens is that the electrician jams the neutral wire into the lug, but then neglects to tighten it. It later rattles loose enough to create the problem, but passes the initial smoke test - probably due to the lack of actually testing it under load.

author: Alana
author_rank: Frequent Contributor
timestamp: January 03, 2014, 10:56:46 pm
content: Quote from: CSmith on January 03, 2014, 09:56:42 pmSeen it and fixed it at one location's fusebox. Thick wires were used as connection from GFI to breakers and it seems whoever assembled it forgot to use screws on those breakers. Worked because wire was thick and acted like contact spring but eventually gave up and i was asked by owner if i can fix mains related problems "because i handle those computers so well".

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 04, 2014, 12:52:56 am
content: Quote from: liquibyte on January 03, 2014, 08:53:42 pmThere are home automation systems (and on a smaller scale, "green" power strips) that can be programmed to turn on loads in response to a master load turning on. Some of them are available as "smart" outlets and hardwired control modules.

author: vk6zgo
author_rank: Super Contributor
timestamp: January 04, 2014, 12:53:42 am
content: Quote from: KJDS on January 03, 2014, 05:45:37 pmVery low volume production yields some interesting results:At my last job,they decided to buy 5 specially designed Transmitters from a Chinese company,at a very reasonable price.On arrival,they had an80%failure rate.After trying the adjustment procedure,we had a100%failure rate,so sent them back to the PRC.When we got them back,they had various modifications,3 of them sort of worked!We eventually had to roll up our sleeves & fix the things ourselves,the "Engineers" at the factory being of no help whatsoever.It turned out to be a combination of poor design,abysmal assembly,& total lack of Quality Control.Mass produced stuff from the same country,except for the really cheap crud, is usually quite good.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: January 04, 2014, 12:56:08 am
content: Quote from: AndyC_772 on January 03, 2014, 10:03:17 amExcept in this case, everything is supposed to be accounted for and there are people who are there specifically for this stuff. That cabnet has actually started filling up again but this time everything has paperwork and isnt piled in there in heaps. When I said no one wanted to deal with it, I actually meant that no one wanted to deal with it, it didnt have anything to do with cost. No one cared to do the tedious job of troubleshooting and paperwork.(god, the amount of paperwork required...) You know how everyone always has other stuff they are 'busy' with?I actually took a crack at some of the stuff in there today and yesterday. The guy who takes care of all the nonconforming stuff(clearing it for wherever it needs to go) will now have a surpise box of stuff when he gets back from holiday on monday. haha (seriously I would put the typical rate he receives stuff from our area at maybe a couple items a day and I just loaded like 10-20 times that onto his shelf haha)

author: dfmischler
author_rank: Frequent Contributor
timestamp: January 26, 2014, 01:23:15 pm
content: Sometime in the late '80s I ran a software group that had to build systems that integrated equipment with embedded micros and multi-user computer systems (DEC PDP-11 and VAX at that time). We had a DECPDP-11/83that we used for a lot of development purposes (including cross assembly for the micros). It had big disks (for the time), 9-track tape drives for backup, lots of serial terminals, a dialup modem or two, and ethernet to talk to our little VAX. The 11/83 left DEC with an 18 MHz clock (I'm sure it was divided down before use), and it was the fastest PDP-11 CPU DEC offered at the time. Memory was maxxed out, too. But I needed more horsepower.Late one night, I popped the CPU board (DECM8190) and spotted the 18MHz crystal to the right of the DCJ11 CPU (large white substrate with two leadless chip carriers on it). I went over to the hardware lab and pawed through the crystals until I found a 24.00 MHz crystal, and soldered it in place. The system came up at this clock rate but crashed as soon as the operating system booted. I went back and found a 22.1184 MHz crystal. That one worked, and even passed all the diagnostics I could think of to run (CPU, floating point, cache, RAM, KDA50 disk controller, etc.). I left it that way. I never told my boss, or any of the programmers who worked for me (although at least one commented that the system was running very well). And I certainly never told the field service people who came to do preventive maintenance on the system.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: January 26, 2014, 11:56:26 pm
content: Quote from: dfmischler on January 26, 2014, 01:23:15 pmHaha, that is hiliarious. I can just imagine some of the yelling/what have you taking place if they had found out. I have to wonder if this was possibly one of the first examples of "overclocking" done to a system.

author: rexxar
author_rank: Frequent Contributor
timestamp: January 27, 2014, 12:35:06 am
content: You're a braver man than I, soldering new parts on a multi-thousand dollar machine

author: digsys
author_rank: Unknown
timestamp: January 27, 2014, 01:14:42 am
content: Quote from: dfmischlerBack when there were only XTs running at 4.77MHz, just before ATs arrived (at 6-8MHz) and were quoted at over $1,000 more (Just forthe M/Board, NO memory), I got a contract to "soup-up" the XTs. It involved determining which ICs were the bottleneck and replacingthe LSs with F versions (mainly in the clock and address lines). I was paid $50 for ~5.5MHz, $100 for ~6-6.5MHz and $200-300 for ~8MHz.CPUs ran hotter and only "fixed" on the 8MHz+ ones. They sold like hotcakes ... they just told customers they were a "special" release :-)

author: dfmischler
author_rank: Frequent Contributor
timestamp: January 27, 2014, 02:34:01 am
content: Quote from: Tinkerer on January 26, 2014, 11:56:26 pmI'll bet that somebody tried overclocking the first digital computer ever built, although I'm not sure it was when nobody else was looking.Quote from: rexxar on January 27, 2014, 12:35:06 amI figured if it died then I would simply solder the 18 MHz crystal back in before calling field service to swap the board. My people would have kept quiet. I knew from the trade press that prior to release the CPU was expected to run at well over 20 MHz. I later found out that the gate arrays for bus arbitration, etc. were the limiting factor on that board.

author: notsob
author_rank: Frequent Contributor
timestamp: January 27, 2014, 03:03:38 am
content: Beware the marketeers, I onced 'upgraded' a system to a higher 'performance' level, for which the customer had to pay extra per months (leased system). The upgrade was to remove a card, yep that was the upgrade, apparently it had been designed and installed by the manufacturer to steal memory access cycles from the cpu and make performance slower, so that they could later sell an upgrade.

author: dfmischler
author_rank: Frequent Contributor
timestamp: February 09, 2014, 02:11:33 pm
content: I once had a boss (call him "Mike") with a really laissez-faire attitude to what we were building. Mike never showed up for design meetings/reviews and seemed perfectly OK with whatever we wanted to build. This went on for some time, and then Mike went on vacation for two weeks (big mistake). Mike's boss ("Jim") started showing up to "take over" while Mike was on vacation. It didn't take Jim long to realize that Mike hadn't been working with us very much. Apparently Mike had also been begging off from executive meetings by saying he was too busy working with us. The day Mike got back from vacation Jim went to see him, and told him he was fired. Mike cleaned out his desk, and Jim saw a well-thumbed book on antique radio collecting and restoration, apparently Mike's hobby. When Mike tried to take the book home, Jim told him that the company had clearly paid plenty for that book and it was going to stay with the company.I wonder how long Mike would have gotten away with sitting in his office reading his book about antique radios if he hadn't gone on vacation...

author: dfmischler
author_rank: Frequent Contributor
timestamp: March 26, 2014, 02:56:26 pm
content: At my first job in the industry my job was mainly to write firmware for embedded systems. We got a contract to build equipment for a factory parts tracking system for a DOE installation. This was before ethernet was cheap and widespread. So we had to fit into what the plant was already using: 3270 Bisync. Half duplex.Each of our boxes had a short-haul modem, and a synchronous communications controller.The hardware guys chose a new chip that we had never used before: the 2661 EPCI. Ours were from Signetics, but Motorola was also apparently making them. I read the datasheet and wrote some code to make it go. It worked just fine for async communications, but I couldn't get it to work right for synchronous reception. It never synchronized. After going through the datasheet multiple times, I sat down with the hardware designer and we went over my code and the datasheet. He was stumped, too. He told me to contact Signetics and ask them how to make the chip work.I talked to a guy from Signetics who was obviously very smart, but he had a pretty thick accent that made it hard to understand him. I told him how my code worked and how I knew that the chip wasn't working (mainly what I could see with a HP 1640B Serial Data Analyzer). He told me to send him the chip that I was using and he would test it. When I spoke to him the next day he said the chip worked fine. I told the hardware designer about this and he grabbed a scope and the datasheet and told me to give him a short loop on the In-Circuit Emulator that kept writing to the chip. Within 5 minutes he showed me that the data hold time spec on the EPCI was not being met, and he rigged my board to use an existing memory timing one-shot for the EPCI write line as well. Why it worked for async data but not for synchronous I'll never know. This was really an important learning experience for me.

author: dr_p
author_rank: Frequent Contributor
timestamp: April 02, 2014, 02:01:30 pm
content: A project manager and a service engineer (!) are trying to solve a problem: a smart 48V power supply goes into FAULT because the backup batteries have too high of an internal resistance. It shows this and the measured resistance on an LCD. The customer is not happy, so our guys want to make the PSU stop complaining. They did figure out that a fix would be to use (doooh) the proper batteries - low enough internal resistance - but that's too costly. They then looked inside the PSU to find a trimpot so they can "adjust" it. Needless to say there wasn't any.So what they came up with is awesome: put a 0.07Ohm resistor in parallel with the batteries to lower it's internal resistance. It's the second time I explain that it's not going to work, that it's just like shorting the battery with a cable. They listed, they watched the figures (500A, 16KW, fire, boom etc) and said: "OK, but how about we try it, that can't hurt."I'm all about helping people, but third time is a charm, so I gave up and told them to go try it.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 02, 2014, 05:24:41 pm
content: My first week in induction heating (professionally). As an EE, I'm still learning the EDA tools and studying existing designs for ideas before doing new design, so I'm spending a lot of time on the shop floor looking at new units being built, old units in service, etc.I walk past a unit in repair. Talk to the techs. Won't start, current fault. Everything looks good, they replaced the main board, still fails. All the signals look good, transistors are switching properly and all. Hmmmmm.I look deep inside and notice this 'figure-8' component -- it's a dual current transformer, mounted around a copper tube going to the output. (Induction heaters are basically humongous resonant power supplies, so the controller usually has to track resonant frequency somehow, not to mention monitoring inverter current and output voltage. Power levels start in the kW and go up from there, with 480VAC input being typical, and output currents in the 500-2000A range being typical for small units.) As it turns out, this current transformer is indeed a dual device: it's two wound toroids, stuck together and wrapped with black electrical tape. One is, say, 20:1 into the other, which is 20:1 into the terminals, for an overall 400:1 ratio or whatever.As it turns out... that current transformer was looped through the wrong hole. So it was reading an order of magnitude (or so) too high...Having solved the problem in ten minutes, I was subsequently called "Super Tim" by the techsTim

author: IanJ
author_rank: Unknown
timestamp: April 02, 2014, 06:08:21 pm
content: Cost cutting my old boss decided the CCTV system we had bought in (industrial type for system builders) could be powered easier/cheaper by replacing the 2off req'd 24vdc psu's with 1off 48vdc unit......and by hooking up to the two outside terminals and linking the two middle ones.Testing the system he switched it on and blew the arse out of the lot...............he had no idea the system req'd +/-24vdc and not +48vdc. Glad I was on holiday that week.

author: Little Brutus
author_rank: Unknown
timestamp: April 03, 2014, 02:22:09 am
content: Quote from: liquibyte on January 03, 2014, 09:40:37 pmThink of the attached picture on the "Bad" side J3 and J4 are in series instead of in parallel (we will say J4 represents your light (say 100W bulb), and j3 represents your vacuum).Turn on vacuum, nothing works. Close switch S2, vacuum now working, but there is a massive 1200W flowing through the light bulb!edit: should have said, lets say the vacuum draws 1100W.....

author: David_AVD
author_rank: Super Contributor
timestamp: April 03, 2014, 09:21:08 am
content: Quote from: Little Brutus on April 03, 2014, 02:22:09 amNo, the vacuum would be in series with the lamp. You can't force more power through the lamp unless you raise the voltage.

author: poorchava
author_rank: Super Contributor
timestamp: April 03, 2014, 09:38:49 am
content: It's a story that my mom once told me (she's a power system/grid engineer):In the mid 90's Geologists were doing some surveys drilling out some really deep cores. Accidentally they have drilled through a tram supply line (about a kilivolt of DC) and a high level grid hv distribution line (110kV ac cable). I suppose they wouldn't hit on their first try if they were trying and got accurate coordinates, but they did it by pure accident.The outcome was that one tram conductor has spotted a huge arc between two overhead lines going towards the tram. He only managed to open the door the the passenger compartment and shout "everybody get the fuck out!". Obviously everybody got out of the tram and started jumping on the poor guy for being rude an all that.

author: SL4P
author_rank: Super Contributor
timestamp: April 03, 2014, 01:00:27 pm
content: Aha! here's one from the early 90sSTORY #1Brand new multi-channel digital television facility. Around 50 services being muxed up to the satellite for regional distribution.Well into the final test & commissioning process, a mid-level tech was using a scope on cart to verify signals available on the front of the rack. As one of the design engineers - I had pushed hard to have utility power outlets on the front opf each rack, but "nooo that's not the way we do it". OK.So this guy is well into his test protocol, drawing power from the back pf the rack with door open, and extension cable running around the floor to his test gear.Tech #2 is wandering around in the equipment room between racks, and with no malicious intent, pushes past the back of the rack - squeezing the rear door partly closed. Enough to sever the extension cord in the gap between the rear door and rack frame. No smoke, no major bang - just a lot of LEDs and beepers going off in this very large facility.Which row of racks lost power? The master and backup sync generators, and master clocks for the whole facility. Oops.I can't remember why the dual-fed racks didn't swap to the B-side for power, but they certainly didn't! Perhaps locked out during testing.Story 2:Another large broadcast facility with over 120 x 49U racks in the central equipment area was going through pre-handover testing - with some weird intermittent problems.It turns out that whomever purchased cable and connectors knew nothing about either - and literally thousands of cables had to be re-terminated before the acceptance testing could be restarted.Use the correct crimp connectors on the correct coax cable.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: April 03, 2014, 11:15:48 pm
content: I used to do Audio for conferences, trials and equiries and such.We had an important enquiry involving quite a few deaths and a stack of media, so much media that they overflowed into another room.Anyway I wired up my system in good time and tested it, the IT guys were still figuring out their stuff the and wiring it in the night before.So on the opening day before the enquiry started when I tested my system I found that I had lost one of my output Audio channels and in the 15 minutes as Judges and lawyers were sitting down to start I was frantically trying to find what was wrong.I couldn't see it and so I had to make a quick decision. Who is losing sound for the session? Bench, Lawyers, Media or Grieving relatives.I pulled the Grieving relatives knowing that if I pulled the Media I would never hear the end of it.It was pretty bad, they could see the discussion but couldn't hear.After the first adjournment I went looking for the fault. The network guys had jammed about 50 CAT 5 cables through a hole that I had drilled specifically for Audio. The mechanical pressure of all the cables had deformed the insulation of my Audio cables and shorted them out internally. Jaycar cheapass shit.Anyway it went smoothly after fixing that.