Most "wrong" fun in the lab/shop/biz/bench? Keep it clean! - Page 1
Forum section: electronics / general

author: mkiijam
author_rank: Regular Contributor
timestamp: November 08, 2023, 08:24:08 pm
content: TV repair shop: We had a game we called "One Twenty to the Board." (USA, and are mains power is typically 120V) We would take junk PCB's and attach a stripped AC power cable to two random spots and plug it in. Sometimes nothing, sometimes MASSIVE showers of sparks. More than a few times we would blow the 20amp breaker which was actually next door!We found that the large 40-ish pin chips were the best... they'd look like Roman Candles going off. Tons of fun.

author: jonpaul
author_rank: Super Contributor
timestamp: November 09, 2023, 11:57:38 am
content: Year circa 1960At Radio Row lower Manhattan NYCTAB surplus, 111 Liberty St. Old warehouse, with war surplus store and power supply mfgMy first Summer job: I was just the kid, a go-fer.I learned a LOT that Summer....When closing up, with breakers OFF a tech placed 1 W 10 Ohm carbon comp resistors inserted carefully into the mains outlets.....various places like behind sales counters and mamagement offices.....Next morning the boss (who usually opened up) got a BIG SURPRISE as breakers were turned ON.BANG! SMOKE! FLAME! at each rigged outlet.....Jon

author: tom66
author_rank: Super Contributor
timestamp: November 09, 2023, 12:31:04 pm
content: I have a 300V power supply, sometimes I would put 1k ~ 22k ohm 1/4W resistors across it and watch the fireworks.

author: Dan123456
author_rank: Regular Contributor
timestamp: November 09, 2023, 12:58:12 pm
content: When I was an apprentice mechanic, one of the guys quietly wired the cars ignition coil to the drivers seat and asked me to drive it it… sure enough, I turn the key and feel like I’ve been shot in the buttI still drove the bloody thing into the shop with it zapping me the whole time thoughYou probably couldn’t get away with that these days but was all in good funGood times

author: nali
author_rank: Frequent Contributor
timestamp: November 09, 2023, 01:05:09 pm
content: Early Weller TCP soldering stations had a transformer base on the front with 24V AC terminal posts to connect the iron. A small bead tantalum discreetly wired across the terminals never disappointed

author: Xena E
author_rank: Frequent Contributor
timestamp: November 09, 2023, 07:36:27 pm
content: QuoteHmmmm,However:QuoteHave I got a story for you!QuoteAwww

author: ccktek
author_rank: Regular Contributor
timestamp: November 09, 2023, 08:00:47 pm
content: Late 1960s: One of the engineers in our lab was working on a big rat’s nest breadboard circuit. When he was away we snaked some thin clear plastic tubing into the circuit from a nearby bench. When he returned we blew smoke into the tubing. He first switched off the power supply – more smoke. Then he switched off other attached test gear – still more smoke. Then he frantically pulled out mains plugs – more smoke. Finally he discovered the end of the tubing. In retrospect I wish we hadn’t done it, but that’s what normal young smart-asses do.

author: themadhippy
author_rank: Super Contributor
timestamp: November 09, 2023, 08:26:55 pm
content: A 13A plug with a switch wired across neutral and earth is a fun way of tripping the rcd every time your collage lecturer touches the overhead projector screen,it also results in a boring theory lesson being turned in a practical demonstration of fault finding.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 09, 2023, 10:19:54 pm
content: Two from the dumb teen years.High Voltage supply based on 5U4GB rectifier tubes. Load the output heavily and watch the plates glow red, then white and then melt. Tubes were cheap back then, often free from salvage.Same era. 800 V supply. Made a then impressive bank of capacitors with total value of tens of thousands of microfarads and discharged it through various materials and underwater to create steam explosions to form thin metal. The most impressive and never duplicated in may tries effect was exploding the tungsten filament from a lamp. Exploded in a fireworks display of bright sparks trailing a white filament that remained hanging in the air. The filaments were fragile, but could be capture on a pencil and dragged through the air.

author: coppercone2
author_rank: Super Contributor
timestamp: November 09, 2023, 11:09:31 pm
content: smash lithium primary batteries on a rainy new years eve when the fireworks were dampit can be as good as a failed jumping jackbut don't do this because probobly it can shoot you or something.

author: djacobow
author_rank: Super Contributor
timestamp: November 09, 2023, 11:15:12 pm
content: I have put nails through some charged lithium cells and been rewarded by a jet of flame. But recent cells don't seem to do it? Have they added some new safety features?

author: nctnico
author_rank: Super Contributor
timestamp: November 09, 2023, 11:17:47 pm
content: Quote from: ccktek on November 09, 2023, 08:00:47 pmA long time ago I instigated a more positive prank. One of the older co-workers brought an old style phone that used to be in his parent's house to put it as an ornament on his desk. He claimed it was broken. When he wasn't there we investigated the phone and concluded it could be made to work with some simple fixes using part we had around anyway. So one day we fixed it and patched it into the company's phone system. The face of the guy when it rang and there was somebody at the other end of the line when he put the handset to his ear was just golden.

author: coppercone2
author_rank: Super Contributor
timestamp: November 09, 2023, 11:21:02 pm
content: Quote from: djacobow on November 09, 2023, 11:15:12 pmIDK those have flammable liquid, the primary is reactive metals, so if you smash a leak into it and throw it into a puddle over stone it sometimes get interesting. But like a jumping jack it can probobly fly away or explode and shoot out like a cannon.

author: PwrElectronics
author_rank: Regular Contributor
timestamp: November 10, 2023, 04:28:52 pm
content: Early 90s I worked at a place that did industrial VFD repair.The owner had collected a lot of "stuff" in the basement for plans to make homebrew dynos. Amongst the collection were a lot of current transformers for use with panel meters to measure mains loads.One day after hours, I gathered up a few of them at different sizes and chained them together. Input was a variac off the AC line and the output was a loop of 0000 cable. Put 1500A range clamp on meter on the loop. One could turn up the variac and get I think it was 1200A in that loop.I discovered putting ones hand near that loop made if "feel funny". Not sure what was happening there with the magnetic field and my body but I didn't do it very long!!Couple of years ago I was trying to duplicate some failures the customer had on a item I designed. I eventually got the clue from them that a loose battery negative cable could be involved. Failures only happened during engine starting. So, my test setup had a large 12v truck battery, a contactor I could engage with a push button, a big iron core inductor to simulate the inductance of a engine starter motor and several feet of battery cables. The trigger of the contactor basically shorted the battery through the inductor and cables. So, some large currents with flyback spikes on the loose (deliberately so) bolted joint in the cable was possible. I had lots of flashing and melted ring terminals and the loose bolt. It looked pretty rough by the time I was done. After my contactor stuck once and melted off the cable, I put in a 250A fuse when I replaced it. No need to risk having the battery explode. That type of fuse would pass the current longer than my intermittant engagement of the contactor. I am sure I likely had 1000A in there but didn't try to measure.

author: coppercone2
author_rank: Super Contributor
timestamp: November 10, 2023, 04:55:42 pm
content: that's weird, I have a brazing transformer that I have wired up with 0000 cable. If I stand in the middle of the loop while holding an electrode (with the other one clamped) I feel nothing. Though usually I stand outside of the loop, but it happened before.It does shake stuff though, perhaps you just feel vibrations? The current levels are like 1500 amps+

author: Bud
author_rank: Super Contributor
timestamp: November 10, 2023, 05:45:56 pm
content: Putting your hands close to antenna matching circuit of a few kilowatt transmitter hurts, even if tramsmission frequency is 3.5MHz.

author: CJay
author_rank: Super Contributor
timestamp: November 10, 2023, 06:46:40 pm
content: High value resistor wired from mains live to a pushbutton which connected it to earth.High enough to not be dangerous but low enough to cause a nuisance trip whenever the button was pushed.Drove a colleague insane for *months*Same workshop, different colleague, they went on holiday so we got some really strong double sided adhesive tape and stuck down *everything* on his workbench.Different workshop, in the PSU repair benches we had some basic high wattage resistor dummy loads in fan cooled metal cases that were used for testing, we did all sorts, 'Soundbomb' sirens hidden inside and wired across 12V load, a random chirping thing we found that sounded just like a PSU 'hiccuping', a 555 timer connected to a Piezo, free running high enough to sound like a PSU squealThe worst/best, we were in an industrial unit which had 12ft high brick walls then a 'tin' roof another 10ft or more above.Ideal position for a theatrical flash/smoke pot.

author: mkiijam
author_rank: Regular Contributor
timestamp: November 10, 2023, 09:58:52 pm
content: Another fun one we did to each other, was to walk behind a tech who had is head stick in a TV and clap! You could make the sharp report sound just like a cap discharging which would make them jerk back in shock. No matter how we would prep for the next time, we'd always get fooled... it was like reflex.

author: hans
author_rank: Super Contributor
timestamp: November 11, 2023, 11:46:01 am
content: In my old school you could tell you were on the EE floor of the building.All students would check corded power strips for hidden caps before flicking the switch.

author: Gyro
author_rank: Super Contributor
timestamp: November 11, 2023, 01:38:15 pm
content: Quote from: nali on November 09, 2023, 01:05:09 pmI remember doing the same to a colleague using a low value resistor inside a piece of Hellerman sleeving. He was not impressed by the lazy coil of smoke and pungent stink when he turned his bench on!

author: TERRA Operative
author_rank: Super Contributor
timestamp: November 11, 2023, 03:14:33 pm
content: When I was fixing welders for a few years, we'd sneakily squirt WD40/CRC/etc on the hot weld as someone was testing a welder (Easy when they are blinkered with their head in a welding helmet). Flames are always fun.Also, turning off soldering irons while the tech was deep in concentration halfway through a 20-pin plug.We also found that sharpened tungsten rods fitperfectlyinto the nozzles of our air blowers (The ones you hook up to shop air), they made for somescaryblow darts that were pinpoint accurate and very powerful when shot across the shop.

author: m k
author_rank: Super Contributor
timestamp: November 11, 2023, 03:56:13 pm
content: Ever heard of Anton Svensson from Maple Hill.

author: nali
author_rank: Frequent Contributor
timestamp: November 11, 2023, 03:58:11 pm
content: Quote from: Gyro on November 11, 2023, 01:38:15 pmIf you used Hellermann sleeving you must surely know the trick of putting one on the end of a freezer spray nozzle then folding it back and cable-tying it closed? The spray would inflate it like a balloon which itself would then freeze before going off with a hell of a BANG.Those Hellermann sleeves were used almost everywhere in my apprenticeship days, they were applied with those 3-pronged expanding pliers affectionally known as Honeymoon Pliers...

author: themadhippy
author_rank: Super Contributor
timestamp: November 11, 2023, 05:45:20 pm
content: QuoteDont forget thebaby oilexpensive hellermann lube