When it went wrong due to no fault of the repairman

[ChristianFletcher]

I once repaired a radio that I fully tested and worked very well. Right up until the moment I went to make a brew and returned to my workshop to find my workshop full of smoke and pitch melted over my work bench and yes it was fused. Given that accident happen etc I wonder how the professional repair shops dealt with these kind of failures. I know that many television were the perfect fire trap. Has anyone been unlucky enough to have this type of incident in a professional capacity? I’m thinking bad luck rather than negligence. Or perhaps you dropped the ball and were negligent oops!

Damage was due transformer developing a shorted turn.

Mods. please edit my title meant to say no Fault. Sorry


Thanks Chris

[barrymagrec]

The Cossor 1035 scope I used in my youth did this almost every time I stepped out of the workshop for a minute, it would have been fine all day but a moment of inattention and the room would be full of smoke, usually one of the (3) mains transformers. I had about 4 extra transformers lashed in to overcome various duff windings at one point.

[Cobaltblue]

I also had a 1035 as my first scope I was 16.

It also had an assortment of transformers get get all the supplies

Just like barrymagrec it ended in a bit of a conflagration when I went to see a friend and left it on. The smell hung around for years!

It was replaced by a Hartley 13A I should have stuck with the Cossor.

At the time I was at PCFE doing my RTV1 so trying to become a professional repairman

Cheers

Mike T

[G6Tanuki]

A bit of datacomms-kit I used to support had an issue with the 1488/1489 RS232/V.24 line-driver chips which could, under certain conditions associated with miswiring, overheat and - in extremis - cause the PCB to self-combust.


I had one do so while it was on 'soak-test' and I'd popped out for a brew-and-a-wee.


Once this fault was known-about, we initiated a recall of all the affected boards and - fortunately - the manufacturer paid for both the replacement-parts and the field-service-technician travel/time-costs - though they did get a bit huffity about paying for a tech to fly to the Canary Islands..

One of our competitors failed to replace known-defective boards.... my lips remain sealed for legal reasons.

[duncanlowe]

Not quite the same, but had more than one problem where something went wrong due to no fault of the person who built it.

Both while working for the same company, both due to design issues. First was a rack system. Testing each module in the rack. Got down to the second module in the second rack. Started the test and got smoke. The fact that it was a rack system made it look like a toaster. The problem was depending exactly how the shakeproof fixing washer (specified) sat against the PCB where a power supply track was way too close to the fixing point. Replacing with fibre washers prevented recurrence. I wasn't happy given the pressure to work unpaid overtime in order to deliver.

The second was to do with an upgrade on an existing system. Voltage and current upgrade. The upgrade design, amongst other things, didn't consider the supply to the cooling fan which was simply a fancy PC case fan. It caught fire. All in all, given faults with the module that was to be upgraded, and issues with the design, I think the only thing in the unit the customer got back from what they sent in, was the fan grille.

I didn't stay long as they consistently blamed me for not being able to build stuff!

[ChristianFletcher]

Those transformers have a lot to answer for LOL.

[Refugee]

I was once told to start using some transformers that had been "Saved" from another contract by the boss.
It was a dryfit charger and we did not have any flat batteries to fully test it on so that I could prove that it would come back faulty with an open circuit transformer.
He insisted against my advice.
The job bounced as I said it would with a bit of melted carpet stuck to the bottom of it and an enclosed solicitors letter.
He was one of those bosses that only learned from those "told you so" situations when communicating with engineers.
He let me order the original I had specified and it then worked as I said it would.

[McMurdo]

In the day job I repair a lot of professional audio amplifiers which are by and large stereo, i.e. 2 amplifiers in one box. Around say 40% of the time, the client will report eg. 'channel one fine, channel 2 dead'. I repair channel 2 and test it, whereupon, for sake of completeness, I check channel 1 and it blows up with some obscure pre-existing fault the customer was not aware of.

Convincing the customer it's not my fault is another matter.

[Heatercathodeshort]

Not worth the stress, argument and loss of faith by the customer. I used to cover the cost of whatever had gone pop while the items were under repair. It was a rare happening thankfully. John.

[lesmw0sec]

I recall a bit of nucleonics kit where a Parmeko oil-filled transformer exploded with such force that the steel rack was dented - then there was the oil to mop up...

[Welsh Anorak]

Like John says, it's just not worth the argument.
Regarding recalls or bouncers whatever you say it will be your fault for not having fixed it properly or not spotted the thing that was about to fail. Trying to put it in terms they can understand (say car metaphors) isn't worth the time. I usually tell them it was unrelated but there's no charge. Often you get a tip and usually a happy customer.

Of course sometimes it's the customer who has actually broken it - like the 50" TV on the bench today that had no picture due to the customer having used 2" woodscrews to secure the stand and drill two neat holes in the T-CON board! No argument there...well, not till he gets home!

[Outrun_uk]

Originally Posted by Welsh Anorak

Of course sometimes it's the customer who has actually broken it - like the 50" TV on the bench today that had no picture due to the customer having used 2" woodscrews to secure the stand and drill two neat holes in the T-CON board! No argument there...well, not till he gets home!

If you try and make something foolproof the world will invariably present a better idiot….

[Lloyd 1985]

Not a repair as such, this was a batch of brand new things (a computer with a load of RAID storage for film industry stuff) that went very wrong! There were 3 of us working late one night, we had built up 15 of these new fangled computer things, which were modular, the main computer bit with a touch screen sat on top, then there were extra modules, with either RAID storage, or some LTO tape drives, they were all sat on the bench powered up ready to run some RAIDtest’s on the drives, and the other 2 guys decided it was time to go home. Just as they were going out of the door there was a smell of burning, me and the boss were looking around to see where it was coming from, then one of the units stopped it’s raidtest with a load of errors, and you could then see the smoke coming out of it! We yanked the plug quick! I opened it up, and found the glaring error, the backplane PCB for the drives had gone up in smoke, the bracket it was fixed to was touching the edge of the PCB, and it must have had the positive rail for the power supply right near the edge, so it was shorting it out, but only just! We had noticed the board was a tight fit on the bracket! Once we had found it we decided it’d be best to switch off the remaining units, which were actually working fine, and we modified the bracket, simply filing off the bit that touched the boards. Only took another 3 hours, but all the units were then safe, and went off to the trade show the next day. The drawing for the bracket was updated with our ‘mod’! And I think the units were fairly successful, we certainly built a lot of them after that!

Regards
Lloyd

[John10b]

I remember when I was an apprentice in the fifties accompanying the field engineer to a call out to see why a customers tv had caught light. Fortunately no one was injured and only smoke damage in the living room.
My memory is a little sketchy and I don’t remember the make of tv, but it was the mains dropper which had caused the fire, unfortunately the customer had a thick cover on top of tv, with a large flower pot on top.
It was common practice to cover TVs when on soak test in the workshop to try and simulate domestic conditions, as many sets sat right next to open fires.
John

[SiriusHardware]

In a past life I looked after, among other things, town centre CCTV camera systems. I got a call from a small town in County Durham saying that one of their cameras was off, but when I actually got there I was greeted with the news that something like one in three of all of the cameras were off, dotted around at random locations across town. What on earth could this be, and why was it only affecting some of the cameras and not others?

I went for a stroll along the high street - as with many such small Durham towns even today, the mains supply wiring was carried along the street airborne on wooden poles like telegraph poles. As I neared the far end of the street, I spotted an electricity board van parked up near one of these poles with a couple of guys up in the air on its built-in cherry picker, and finally the penny dropped. I walked over to them and said, cheerfully, "Excuse me gents - you don't by any chance have one mains phase off, do you?". "Yes" came the reply.

With all of the cameras and their control cabinets mounted on roofs or under eaves, I had been very close to calling out an expensive cherry picker.

[Maarten]

Originally Posted by Outrun_uk

If you try and make something foolproof the world will invariably present a better idiot….

Putting the TCON on the bottom of the set is a weird habit that started more than 10 years ago, maybe there were reasons for it, but it's less foolproof than the opposite, also because of liquid ingressions in the connections to the LCD itself.