most broken equipment you run into? - Page 1
Forum section: electronics / repair

author: coppercone2
author_rank: Super Contributor
timestamp: December 09, 2023, 07:07:29 pm
content: What equipment do you think breaks the most?IMO from what I have seen, its either scopes or power supplies. In terms of breaking without a bad user, its scopes IMO. Lots of broken supplies because of solenoids or batteries, but scopes just break.In the repair equipment closets I seen, scopes seem common.And they are usually treated better, since supplies are cheap compared to scopes.

author: Zenith
author_rank: Frequent Contributor
timestamp: December 09, 2023, 07:56:22 pm
content: Scopes don't just break, they can struggle on for years being useful to the owner with only one channel working, or the triggering not working properly, or some feature not working, etc. Back in the day they were expensive prized possessions, and wouldn't be lightly thrown away, even if they didn't work at all. There were commercial repair services, but they were quite expensive. I'd say that power supplies were more likely to be thrown away.Scopes are almost certainly inherently less reliable than power supplies because of complexity, many switches and controls which can cause problems and very high voltage circuitry.I haven't taken a count, but I have the impression I see more second hand/junk scopes than bench power supplies. Maybe it's just that I notice the scopes.I don't see many of those little analogue multimeters around that were popular in the 60s and 70s. They were fairly easy to damage and most people would prefer a DVM. There'd be much less reluctance to throw one away.

author: coppercone2
author_rank: Super Contributor
timestamp: December 09, 2023, 08:03:42 pm
content: i still see it with new scopes thoughlike keysight

author: MadTux
author_rank: Frequent Contributor
timestamp: December 09, 2023, 08:05:13 pm
content: Well, with oldish Tek scopes, unless tube or a few custom parts break, it's all user fixable, even tube and ASICs can be salvaged from part units.Nowadays, break any custom chip in a scope and it's usually bricked. Unless you have BGA rework station and a unit for scrap to salvage parts, you're screwed.Then shitloads of programmed parts, too. Where you usually can't get firmware for.Power supplies, until maybe 2000s, it's usually easy fix, unless VFD display or something.It's even fricking welders, nowadays. Imagine that thing for 20years in metal dusty workshop, electronics fry for some reason and you have the fun of fixing it.https://www.mikrocontroller.net/topic/557851

author: Zenith
author_rank: Frequent Contributor
timestamp: December 09, 2023, 08:26:52 pm
content: Quote from: MadTux on December 09, 2023, 08:05:13 pmLow end amateur grade inverter stick welders are a likely contender. They are built on the cheap, they are kept in damp sheds and often showered with metal particles. No conformal coating or channeling to direct the cooling air only to the heatsinks. They are very clearly not intended to be repaired and there's very often no service information at all.El cheapo SPMSs cause a lot of problems.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 09, 2023, 08:41:24 pm
content: Quote from: coppercone2 on December 09, 2023, 07:07:29 pmMaybe a better question is what have you seen people do the most often that damages equipment?

author: MadTux
author_rank: Frequent Contributor
timestamp: December 09, 2023, 08:43:14 pm
content: Quote from: Zenith on December 09, 2023, 08:26:52 pmChinesium and cheap Fronius stick welders are horrible throwaway items, from what I've heard.That Rehm one, isn't exactly a cheapo, though ;-Dhttps://www.weldingtool.eu/rehm-wig-schweissgeraet-invertig-pro-compact-280-ac-dc-digital-ohne-zubehoer.htmlMiss the old days, where everything was sectioned onto plugin cards and you get a 500page service manual, with schematics.

author: coppercone2
author_rank: Super Contributor
timestamp: December 09, 2023, 08:59:18 pm
content: Quote from: joeqsmith on December 09, 2023, 08:41:24 pmlike use it once in a while for <10V signals when its sitting in a closet with cover on most of the time

author: Kim Christensen
author_rank: Super Contributor
timestamp: December 09, 2023, 09:07:15 pm
content: Quote from: joeqsmith on December 09, 2023, 08:41:24 pmProbably the worst are those instruments that have a sensitive input. Like a milliwatt RF power meter or RF signal generators that people accidentally connect to a 100W+ transmitter.Another one that was really bad was theFluke 725 Multifunction Process Calibratorwhich looks a lot like a regular Fluke DVM. The electricians would confuse those with a DVM and blow them up all the time by measuring mains voltages with them.

author: MadTux
author_rank: Frequent Contributor
timestamp: December 09, 2023, 09:28:02 pm
content: Those Fluke calibrators are a joke anyhow, $4000 each and not even 1000V tolerant input.Not like those are for lab use only, 3phase 400VAC all around, where these things mostly live.Fluke probably gave them banana jacks on purpose, each time some unsuspecting noob connects more than 30V to it, good repair/replacement money for them. ;-D

author: Zenith
author_rank: Frequent Contributor
timestamp: December 09, 2023, 11:12:49 pm
content: Quote from: MadTux on December 09, 2023, 08:43:14 pmIt's the way the world has changed. In the days of valves (toobz) repairing TVs was a considerable industry. These days TVs last for years and when they fail, I doubt they can be repaired. I was talking to the people at the local dump about the TVs and monitors they take. They said they almost all work. Most people get rid of them because they are too old.

author: antenna
author_rank: Frequent Contributor
timestamp: December 09, 2023, 11:17:17 pm
content: 5kΩ pots

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 09, 2023, 11:32:04 pm
content: I believe Coppercone is correct, its either PS or Scopes. but these are the most common equipment anyway.I used to pick up scopes and PS at hamfests and fix them, If i got a nice one I would keep it, otherwise sell for my TE fund.But now, with the advent of new DSOs being so nice and cheap, it does not pay to refurbish old scopes. In my part of the country at least, some really nice old tek scopes are going for less than $100. Would have purchased them just a few years ago.On the broken old scopes, it was usually something like a burned input FET and a quick fix. You could pick up a quick couple hundred bucks this way. Not so with the new DSOs.The PS are becoming more and more switching, so they are harder to repair, probably not worth it. I still try to pick up Big Linear PS when I can. Lots of radio operators are always looking for them. Pretty easy to fix if the transformer is not burned. Does not seem to be much of a market for Lab PS though.I picked a uninterruptible NEG 48 volt PS off the ground at a hamfest after the vendor left it. I fixed the thing and now both PS work. If anyone wants to pick it up for cheap, I am in Indianapolis. This is a telephone company PS.

author: coppercone2
author_rank: Super Contributor
timestamp: December 09, 2023, 11:48:55 pm
content: but what I am saying is that I see DSO failing that are not used much and new ! like tektronix etc. anything from front panel buttons to channels going off. that stuff has repair tag on it ALOT

author: floobydust
author_rank: Super Contributor
timestamp: December 10, 2023, 12:51:41 am
content: #1 busted test equipment I see at work is bench power supplies. I went through over 6 repairing them and adding protection diodes if they were missing.No engineering budget dollars to buy new ones, so I simply fixed them while jr. engineers were bamboozled I would take them apart and knew what I was doing in there.For other tagged test equipment, it can be people not knowing how to use it and thinking the scope is defective when it's not showing what they want or expect.I was doing probe comp and again the jr. engineers were fascinated what I was doing turning a trimcap in the probe so square waves looked proper.

author: xrunner
author_rank: Super Contributor
timestamp: December 10, 2023, 01:07:36 am
content: Quote from: floobydust on December 10, 2023, 12:51:41 amYep power supplies and power testing equipment. I sometimes help out a local company that makes a few products because I know the owner. I just repaired a Topward TPS-4000 for him which had a broken power switch (the metal switch stem was snapped off). He also has a Agilent 6050A electronic load which has a suspiciously loose AC input connector. Might be dangerous I don't know yet. But they are both heavy and people have trouble moving them around. So I guess my answer to the question is - anything that is very heavy is some of the most broken equipment out there.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: December 10, 2023, 08:52:44 am
content: Probably not what coppercone was looking for or expecting:anything from my father's age which had bakelite cases, like simpson meters. It seemed everything we had in bakelite had a corner chipped off. They still functioned ok, so not really in the totally fuxored category. Out of curiosity I googled and found you can still buy Simpsons new! $1000+ canuck bucks at Mouser.ca.https://www.mouser.ca/c/test-measurement/multimeters-voltmeters/analog-multimeters/?m=SimpsonWhat the hell? who is buying these?I had a colleague that was expert in overloading function generators and blowing them out. Not sure if that qualifies either.

author: coppercone2
author_rank: Super Contributor
timestamp: December 10, 2023, 09:19:04 am
content: I can totally see someone using an analog meter for doing regular shit. its like visible and you learn what the needle bounce could mean for regular circuits.and if you are doing brain-dead measurements then just knowing the needle % is way easier then interpreting a numberalot of people can't stand number clocks even, let alone number meters, the digits are like imposing, the dial tells you like a percent ofLOL at what would happen if cars only had a # display

author: factory
author_rank: Super Contributor
timestamp: December 10, 2023, 05:45:13 pm
content: Ebay's reporting algorithm, it seems to reject every report I make for; search manipulation, brand name spamming and incorrect catagories.David

author: Kim Christensen
author_rank: Super Contributor
timestamp: December 10, 2023, 06:30:35 pm
content: Quote from: chickenHeadKnob on December 10, 2023, 08:52:44 amMaybe someone who doesn't want to rewrite old test procedures. Sounds like something the military would do.

author: coppercone2
author_rank: Super Contributor
timestamp: December 10, 2023, 06:31:49 pm
content: well do you wanna tell 18 year old "its just like driving a car" or electrical theory

author: abeyer
author_rank: Frequent Contributor
timestamp: December 10, 2023, 09:30:00 pm
content: So the original question was just "equipment" but didn't really specify what qualifies, and people just jumped to test equipment... But in my opinion, everyone seems to be overlooking the likely far-and-away winner of cell phones here -- they're almost certainly the most broken given the combination of sheer quantity and being carried around in inhospitable environments on a daily basis.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 10, 2023, 10:50:06 pm
content: I think you're seeing some bias just because scopes and power supplies are so prevalent, though there are a few others that are common and maybe don't feel like they fail as much.But RF equipment has some kind of failure frequently, often due to misuse (easier to do, more risky conditions, more sensitive inputs/outputs, etc.), but also just to aging. Amplifier stages often run hot and just by leaving it on for long enough, you see a good bit of older RF gear which just needs an amplifier somewhere in the chain replaced, but you'll see mechanical failures of attenuators and things too. Then again, some of this may be the bias that fewer people are attempting to actually repair them.As someone who's seen a lot of faults... I don't think there's a class of instrument that stands out as more likely to fail. There are bad designs, commonly failing components or elements, and equipment/interfaces that are more likely to be abused, but on the whole things are much more similar in terms of non-user-error faults.

author: factory
author_rank: Super Contributor
timestamp: December 10, 2023, 10:53:45 pm
content: Quote from: coppercone2 on December 10, 2023, 09:19:04 amThere are some cars that don't have an analog speedometer, the Citroen C4 being one example, thankfully only had that PoS for a day or two over 10 years ago.

author: Paceguy
author_rank: Regular Contributor
timestamp: December 10, 2023, 11:17:05 pm
content: Lately, it's been much of the stuff that I purchase on ebay. Badly packaged by careless sellers

author: coppercone2
author_rank: Super Contributor
timestamp: December 11, 2023, 12:05:03 am
content: qualified to work in a body shop after only 15 deliveries

author: lugaw
author_rank: Regular Contributor
timestamp: December 11, 2023, 05:32:06 am
content: It looks really really bad on the outside but miraculously the inside survived without damage and it is very accurate because of the year 2020 calibration.I also had a Tektronix AWG615 that looks pristine on the outside but has a shorted 3.3v rail I can't fix. :/

author: RaymondMack
author_rank: Regular Contributor
timestamp: December 11, 2023, 10:19:59 pm
content: In my experience, anything mechanical will become faulty at some point. Particularly silver coated switch contacts. I have probably spent more time replacing and/or cleaning damaged/oxidized switches and bad capacitors than bad ICs. I recently repaired 4 different Agilent E36xx series PSUs (approx. 2008-2011 MFD) that had faulty "gold plated" switches made by C&K (on the back side for slave/master operation and remote voltage/current programming). Ended up just putting wire jumpers in place of the switches since they were so damn expensive to replace (replacement switches would have costed more than I paid for the PSUs).Slide switches are pretty easy to mangle from excessive force and most are not sealed well (if at all), allowing atmospheric gases to easily reach the contacts and induce oxidation. Many, HP/Agilent PSUs use these.Rocker switches can seize (contacts weld together) in AC mains switching (the contacts generally fail before the rocker action does).Toggle switches are fairly robust, but are easy to hit and damage accidentally.Rotary switches are robust mechanically, but oxidize the easiest and are a pain to clean.Large push button switches are quite fragile (especially locking types). I mostly see the plastic stems break off or the push mechanism seizing from either dust/contaminates or mechanical wear of the track.Since most analog PSUs (especially from HP/Agilent) have at least one or more of the above switches... I'd vote analog adj. DC PSUs as the most likely to fail TE.

author: coppercone2
author_rank: Super Contributor
timestamp: December 11, 2023, 10:41:19 pm
content: and sealed relays don't do too well either.. they often have vent holes. its not a good featurebasically its a vent for whatever the switch makes switchingif you seal it up things get trashed

author: KrudyZ
author_rank: Frequent Contributor
timestamp: December 16, 2023, 05:22:11 pm
content: Quote from: lugaw on December 11, 2023, 05:32:06 amBecause you can't find the location of the short or why?

author: ifonlyeverything
author_rank: Regular Contributor
timestamp: December 16, 2023, 06:34:54 pm
content: Quote from: Paceguy on December 10, 2023, 11:17:05 pmWent through this with SMPS transformer ferrites and AliExpress sellers. Three different sellers, in fact. Careless idiots.

author: DrijSkij
author_rank: Contributor
timestamp: December 18, 2024, 03:42:53 pm
content: I dumpster dived a TopWord 6306A from work a month ago. Both Master and Slave didn't work. When I got it home and turned it on there was some brief smoke coming out of the case.After finding a schematic from this site that was pretty similar, but not exact to this power supply, I found that the first relay on the Master side was blown out. Then to find out the cause of it. It turns out one of the main power rectifiers coming off the big tramsformer was quite nicely shorted, and took out its anger on the poor relay.So I replaced the relay(it cost about $1) and I found an old rectifier from work. Fixed it nicely.Then on to the Slave side. This one took some time. After some serious examination, someone took out (desoldered) the two VERY necessary emitter feedback resistors following both of the large pass transistors. I couldn't believe it ! It was so neatly done and hardly noticeable. Initally I was angry and then it eventually became amusing.

author: AndyC_772
author_rank: Super Contributor
timestamp: December 18, 2024, 04:03:54 pm
content: Quote from: Zenith on December 09, 2023, 11:12:49 pmI have a plasma TV in my spare room. It *almost* works perfectly, but under some circumstances shows a purple speckle pattern over bright parts of the screen.Is it usable? Sure, I use it to watch Youtube videos whenever I ride my exercise bike. Most of the time it's perfectly fine. The image is a bit noisy, and of course it gets warm, but that's just normal for the age and technology of the set.But is it worth *anything*? I doubt it. Couldn't sell it as "fully working" because it isn't. I think I paid something like £25 off Ebay for it, and that was about 4-5 years ago.So, suppose I want the space, or a better TV. What would you do with it? I'm thinking the tip is a pretty attractive option.