What is the worst thing you or a customer has done to a circuit? (smaller photos

[vk6zgo]

"Caramello koala" chocolate bar in a Commodore 64 keyboard!

[cdev]

A very long time in a galaxy far away I worked for a while doing very basic repair of audio/video equipment and electronic musical instruments. It was quite routine to have customers come in with vcrs and stereo equipment that had become a favored resting spot of their cats, which led to them becoming clogged with fur.

Whenever starting one of these repairs because the customers would rarely believe what would happen particularly with VCRs unless we showed them, we would take a small cardboard box and put all the fur from that specific repair into the box. Several times there was such a substantial amount of fur that it filled a fairly large box. I remember fixing a gentleman's Betamax VCR that had many many handfuls of extremely fluffy fur in it.

It is amazing that they didn't fail sooner.

[little_grey]

back in the days where i was probably posting toast or cookies into the VCR slot

[IanMacdonald]

Oh, and there was the medical center server that had one more data volume than visible disks.    Opened it and found the additional disk sellotaped to the chassis. 

[gfiber]

30 years ago I was working as a tech at a Marine Electronics shop. A customer came in and asked if I could look at his brand new King 7000 VHF Marine radio as it would not power up. The King 7000 was a very small 25 Watt Marine VHF transceiver. This customer wanted to mount it on the boats overhead and thought it would look better by not using the mounting bracket. The top of the radio was reverse able to make it easier to operate when mounted above. The top fastened with 4 mounting screws. So this customer and his buddy decided to just drill 1/4 inch holes through the radio where the mounting bolts fastened the top onto the radio. Then they could use wood screws to attach it to the overhead.

They very apparently never removed the top, just drilled right through. When I opened that radio the drill bit had grabbed the PC Traces that were near the 4 holes and tore them off the circuit board. I just looked, shook my head and handed it back to them after pointing out their mistake. So much damage it could not be repaired.

[mikerj]

For obvious reasons i am not going to say who i work for,

Having owned a couple of Austin Rover products in my past I know of Pektron

[innkeeper]

Worst thing?

A customer had a go at an older switching power supply that screw terminal caps that bolted directly to the pcb.
They re-attached them backwards before sending it to us for repair.
My buddy on the bench next to me powered it up on a variac, not knowing they were in backwards. he had enough time to yell duck.
after the explosion, there was confetti in the air and 2 holes in the acrostic ceiling where the two cans of the caps blew a hole in them and many ringing ears.

[little_grey]

well that puts my latest to shame.

I did something wrong, still working out exactly what.

it blew up, not quite as dramatically but it certainly made me jump

[CJay]

Back in the days of top loader VCRs, man had been to pub, returned home, found wife had gone to sleep, decided to watch a film, knelt down to load tape into machine, just as he was about to push the lid down, the night's intake of Guinness decided to make a reappearance.

VCR flooded, Tape left in, machine delivered to us for repair, in a bin bag.

When he told us what had happened, it left again in the same bin bag.

[CJay]

well that puts my latest to shame.

I did something wrong, still working out exactly what.

it blew up, not quite as dramatically but it certainly made me jump

used to be a guy who contributed to Television Magazine, Steve Czynski I think (massive apologies as I'm sure i've spelled that wrong) who had a scar on his face from a lump of epoxy that embedded itself in his face when he froze a frame output IC that had gone into thermal shutdown.

[little_grey]

Turned out the boss gave me the wrong wiring diagram.
i only had an image of the chip legs so looked fine.

ended up creating a dead short from the voltage regulator into ground.
after that several components must have given up. got several tracks blown off the board too.

oh well, safety glasses in future.

[carl_lab]

Turned out the boss gave me the wrong wiring diagram.

Of course, the boss... 

[tszaboo]

They blow it up, of course.

[little_grey]

Turned out the boss gave me the wrong wiring diagram.

Of course, the boss... 

yeeaa the boss 
but i should have double checked the part numbers
i will in future

[schmitt trigger]

oh well, safety glasses in future.

I witnessed a similar accident, and it has made me a believer of using safety glasses when dealing with high power stuff. Specifically batteries.

Turns out this technician dropped a screwdriver on an UPS battery bank. Even though his face was perhaps 3 to 4 feet away from the batteries, the ensuing explosion spewed enough metal that a tiny metal shaving made it all the way into its cornea.

Did not lose the eye, but he had to endure a couple of surgeries and had to wear glasses afterwards.

[Cerebus]

oh well, safety glasses in future.

I witnessed a similar accident, and it has made me a believer of using safety glasses when dealing with high power stuff. Specifically batteries.

Turns out this technician dropped a screwdriver on an UPS battery bank. Even though his face was perhaps 3 to 4 feet away from the batteries, the ensuing explosion spewed enough metal that a tiny metal shaving made it all the way into its cornea.

Did not lose the eye, but he had to endure a couple of surgeries and had to wear glasses afterwards.

I used to have a 1950's vintage book on industrial accidents. One plate showed the cauterised hole in a man's shoulder, above the lung but below his collar bone, where the spanner that he'd dropped onto a submarine battery bank went through him after it had become a lump of high velocity molten metal. After seeing that I started treating lead acid accumulators with more respect than I had previously.

[Gyro]

Ouch, Submarine batteries... There are tales of people having witnessed instances of ball lightning from the switchgear on those!

[little_grey]

ball lightning is still something which completely alludes my understanding
i just cant see how its possible