Author Topic: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!  (Read 2286 times)

0 Members and 1 Guest are viewing this topic.

Offline mkiijamTopic starter

  • Regular Contributor
  • *
  • Posts: 164
  • Country: us
Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« on: November 08, 2023, 08:24:08 pm »
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.
 
The following users thanked this post: TERRA Operative, Dan123456

Offline jonpaul

  • Super Contributor
  • ***
  • Posts: 3656
  • Country: fr
  • Analog, magnetics, Power, HV, Audio, Cinema
    • IEEE Spectrum
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #1 on: November 09, 2023, 11:57:38 am »
Year circa 1960
At  Radio Row   lower Manhattan NYC
TAB surplus, 111 Liberty St. Old warehouse, with war surplus store and power supply mfg


My 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
An Internet Dinosaur...
 
The following users thanked this post: Dan123456

Offline tom66

  • Super Contributor
  • ***
  • Posts: 7336
  • Country: gb
  • Electronics Hobbyist & FPGA/Embedded Systems EE
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #2 on: November 09, 2023, 12:31:04 pm »
I have a 300V power supply, sometimes I would put 1k ~ 22k ohm 1/4W resistors across it and watch the fireworks.
 
The following users thanked this post: Dan123456

Offline Dan123456

  • Regular Contributor
  • *
  • Posts: 199
  • Country: au
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #3 on: November 09, 2023, 12:58:12 pm »
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 butt  :-DD

I still drove the bloody thing into the shop with it zapping me the whole time though  :-DD

You probably couldn’t get away with that these days but was all in good fun  :) Good times  :)
 

Offline nali

  • Frequent Contributor
  • **
  • Posts: 732
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #4 on: November 09, 2023, 01:05:09 pm »
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 :)

 
The following users thanked this post: Dan123456

Online Xena E

  • Frequent Contributor
  • **
  • Posts: 686
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #5 on: November 09, 2023, 07:36:27 pm »
 
Quote
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 butt 

I still drove the bloody thing into the shop with it zapping me the whole time though"

Hmmmm,  ???   :-//

However:

Quote
Most "wrong" fun in the lab/shop/biz/bench?

Have I got a story for you! :-+

Quote
Keep it clean!

Awww  :-[

 
The following users thanked this post: Dan123456

Offline ccktek

  • Contributor
  • Posts: 49
  • Country: us
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #6 on: November 09, 2023, 08:00:47 pm »
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. 
Le chat a ses raisons que la raison ne connaît point.

KØMGP
 

Offline themadhippy

  • Super Contributor
  • ***
  • Posts: 3266
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #7 on: November 09, 2023, 08:26:55 pm »
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.
 
 

Offline CatalinaWOW

  • Super Contributor
  • ***
  • Posts: 5571
  • Country: us
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #8 on: November 09, 2023, 10:19:54 pm »
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.
 

Online coppercone2

  • Super Contributor
  • ***
  • Posts: 11342
  • Country: us
  • $
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #9 on: November 09, 2023, 11:09:31 pm »
smash lithium primary batteries on a rainy new years eve when the fireworks were damp

it can be as good as a failed jumping jack

but don't do this because probobly it can shoot you or something.
« Last Edit: November 09, 2023, 11:13:04 pm by coppercone2 »
 

Offline djacobow

  • Super Contributor
  • ***
  • Posts: 1170
  • Country: us
  • takin' it apart since the 70's
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #10 on: November 09, 2023, 11:15:12 pm »
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?
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 28429
  • Country: nl
    • NCT Developments
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #11 on: November 09, 2023, 11:17:47 pm »
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.
A 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.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
The following users thanked this post: Nominal Animal, m k

Online coppercone2

  • Super Contributor
  • ***
  • Posts: 11342
  • Country: us
  • $
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #12 on: November 09, 2023, 11:21:02 pm »
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?

IDK 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.
 

Offline PwrElectronics

  • Regular Contributor
  • *
  • Posts: 107
  • Country: us
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #13 on: November 10, 2023, 04:28:52 pm »
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.
« Last Edit: November 10, 2023, 04:32:30 pm by PwrElectronics »
 

Online coppercone2

  • Super Contributor
  • ***
  • Posts: 11342
  • Country: us
  • $
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #14 on: November 10, 2023, 04:55:42 pm »
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+
 

Offline Bud

  • Super Contributor
  • ***
  • Posts: 7276
  • Country: ca
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #15 on: November 10, 2023, 05:45:56 pm »
Putting your hands close to antenna matching circuit of a few kilowatt transmitter hurts, even if tramsmission frequency is 3.5MHz.
« Last Edit: November 10, 2023, 05:47:57 pm by Bud »
Facebook-free life and Rigol-free shack.
 

Offline CJay

  • Super Contributor
  • ***
  • Posts: 4136
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #16 on: November 10, 2023, 06:46:40 pm »
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 squeal

The 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.
 

Offline mkiijamTopic starter

  • Regular Contributor
  • *
  • Posts: 164
  • Country: us
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #17 on: November 10, 2023, 09:58:52 pm »
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.
 

Offline hans

  • Super Contributor
  • ***
  • Posts: 1698
  • Country: nl
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #18 on: November 11, 2023, 11:46:01 am »
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.
 

Offline Gyro

  • Super Contributor
  • ***
  • Posts: 10174
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #19 on: November 11, 2023, 01:38:15 pm »
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 :)



I 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! :D
Best Regards, Chris
 

Offline TERRA Operative

  • Super Contributor
  • ***
  • Posts: 3169
  • Country: jp
  • Voider of warranties
    • Near Far Media Youtube
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #20 on: November 11, 2023, 03:14:33 pm »
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. :D

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 fit perfectly into the nozzles of our air blowers (The ones you hook up to shop air), they made for some scary blow darts that were pinpoint accurate and very powerful when shot across the shop.
Where does all this test equipment keep coming from?!?

https://www.youtube.com/NearFarMedia/
 

Offline m k

  • Super Contributor
  • ***
  • Posts: 2651
  • Country: fi
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #21 on: November 11, 2023, 03:56:13 pm »
Ever heard of Anton Svensson from Maple Hill.
Advance-Aneng-Appa-AVO-Beckman-Danbridge-Data Tech-Fluke-General Radio-H. W. Sullivan-Heathkit-HP-Kaise-Kyoritsu-Leeds & Northrup-Mastech-OR-X-REO-Simpson-Sinclair-Tektronix-Tokyo Rikosha-Topward-Triplett-Tritron-YFE
(plus lesser brands from the work shop of the world)
 

Offline nali

  • Frequent Contributor
  • **
  • Posts: 732
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #22 on: November 11, 2023, 03:58:11 pm »
I 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! :D

If 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...
 

Offline themadhippy

  • Super Contributor
  • ***
  • Posts: 3266
  • Country: gb
Re: Most "wrong" fun in the lab/shop/biz/bench? Keep it clean!
« Reply #23 on: November 11, 2023, 05:45:20 pm »
Quote
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...
Dont forget the baby oil expensive hellermann lube
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf