What was your easiest repair ever?

[bitseeker]

Glad the fuse died first! Doesn't always work out that way.

[NiHaoMike]

Our lab at work inherited a really nice 1KW switching lab power supply that wouldn't power on.

Turns out the front power switch had failed open. One new power switch later, and the thing works a treat!
Better yet, the power switch was wired up using quick connect plugs. No soldering required!

A very long time ago (when CFLs were just coming out and somewhat expensive), my mom got a fluorescent light at a thrift store for $5 or so. The problem? A bad switch. Bypass it and plug it into a switched outlet.

About a year and a half ago, I scored a WD AC1300 (actually AC1750) router for $15, was sold as a returned unit that "worked but made a lot of noise". Swap the fan with an identical looking one from the parts bin and it was working like a champ. Until now when I noticed the fan is starting to fail again. The fan in the router always starts to fail when the mining cluster it serves has some real work to do, right? Temporary solution is to place an external fan to keep it cool until I can find a replacement.

[mscreations]

Not electronics related, but I service forklifts for a living. One Thanksgiving while shopping at Walmart, I got called out for an emergency repair. At the Walmart. Walked over while the wife finished shopping and took a look. Someone had turned the key to their scissor lift to off and removed the key. No one there had a key. I pulled mine out of my pocket, turned it on and told them we would send the bill. I got paid 4 hrs (minimum call out time) at double rate ($54/hr) for five minutes of my time.

Electronics related, I got 4 computer monitors from my employer that were 18 months old. Took first apart and found blown caps in the power supply. Replaced them in all 4 units and now have 4 monitors for my computer. They've been flawless since they were repaired.

[DDunfield]

Tektronix TDS380 - Engineer at a local company discarded it because "Channel 1 was Wonky".

Turns out someone along the line had replaced the Channel 1 BNC connector with a non-Tektronix one which effectively reversed ground and probe sense (Probe sense ring connected to ground, outside of BNC connected to probe sense).

Took me a couple weeks to obtain the proper Tek part, but once replaced - scope is like new again.

Dave
 

[TheDefpom]

Mine was probably a hp microwave frequency counter, picked it up for about $300, all I did was clean all the card edge connections and replaced 1 capacitor, and it came back to life, ended up selling it for over $1000

[Arek_R]

Owon SDS5032E Digital Oscilloscope, sold as faulty, not working, customer return, physical condition - like brand new.
Got it from ebay for £65, working new one is between £250-£300.
It was powering on but not finishing boot process to UI.
All I had to do was to was to update the firmware using dedicated software, it was not available, but after one month someone got hands on this software and released it, so I update it, and it works just fine!



Kane-May km330 themometer, got it from ebay for £0.99, sold as used, faulty, without the k-type probe.
Brand new is like £100
After I received it and connected it with my probe, it works just fine, dude probably just had broken probe...

[slurry]

That have to be a lab power supply that would'n turn on,
i reached back and pushed the IEC power-connector in fully, then the power supply worked just fine. 

[GreyWoolfe]

That have to be a lab power supply that would'n turn on,
i reached back and pushed the IEC power-connector in fully, then the power supply worked just fine. 

Over the years, I have had quite a few service calls like that.  Or someone kicked the plug in the surge protector just enough to partially dislodge it.  Or the power cord came out of the power supply body.  I would always ask if they checked all the connections and can they do it again and was always assured that they did.  Service solution?  Customer error.

[joeqsmith]

My Sony DSC-RX10M2 decided to stop recording today.    I had bought a Fotga external trigger that I modified with an opto-coupler so I could trigger the camera with various test equipment. 

If I used the trigger button on the camera, it worked fine.   I took apart the Fotga to see if a wire had perhaps broke.   I tested it outside the case and all the signals seemed fine. 

I then tried to trigger it again using the camera's built-in button.  This time it came back with an error that the card was full.   I am not sure why it would trigger that one last time with the camera's built-in button but not the with the external trigger. 

Fairly easy repair, reformat the card.   

[SeanB]

Glad the fuse died first! Doesn't always work out that way.

Common failure on certain avionics was "fail self test", and when i got the wooden transit box and opened it i could smell the cooked insides even though they were hermetically sealed units. Failure was that one of the diodes on the 6 small 3 phase bridge rectifiers that provided internal supplied went short circuit at some time. MC44 diode, 6 per bridge. The 5V rail going short would blow the 1A mains fuses, because that rail had to supply 15A to the unit, so no issues there, but the other rails however would not draw 1A on the primary side into a short. Would work with 1 diode short, just high ripple on the power rail unregulated side ( I checked every unit with a scope looking for that odd shaped ripple on the rails quickly enough), but if a second one went short then the transformer would have a high current flow in the winding, and would gradually heat up.

As the unit was hermetic, this meant no smoke or flame, just a transformer making toxic fumes and eventually getting hot enough internally to destroy the interwinding insulation, typically after dumping a load of liquid melted thermoplastic and varnish byproducts into the case and into the cooling fan. Only then would the primary current be high enough to blow 2 of the 3 1A solder in fuses that provided protection, and the built in test light relay would drop out and show a fail on the master caution panel. I did order some spare power supplies, and I guess Fraser would know the route they took to get there, along with the price of them. Never seen that many digits in an invoice before, for something that was basically fist size, and which I guess was about the price of Promethium per gram, as it was a lot more than Gold, Platinum, Palladium or Rhodium..

[jtu]

Cleaning out dead ants and changing fuse on ~300Eur automatic gate controller: https://www.eevblog.com/forum/repair/nice-automatic-gate-controller-and-ants/

[kulla]

Bought older (but still great) fishfinder Lowrance LCX series that was rebooting constantly.

It turns out that as it had mechanical PATA hard drive inside, humidity got it, so when it starts it would try to spin the disk which would then draw too much current and system would reboot.

Removed the disk and everything worked like it should. Used it for a two years and sold for 3x price of what I paid for it.

It still works

[vk6zgo]

Glad the fuse died first! Doesn't always work out that way.

Common failure on certain avionics was "fail self test", and when i got the wooden transit box and opened it i could smell the cooked insides even though they were hermetically sealed units. Failure was that one of the diodes on the 6 small 3 phase bridge rectifiers that provided internal supplied went short circuit at some time. MC44 diode, 6 per bridge. The 5V rail going short would blow the 1A mains fuses, because that rail had to supply 15A to the unit, so no issues there, but the other rails however would not draw 1A on the primary side into a short. Would work with 1 diode short, just high ripple on the power rail unregulated side ( I checked every unit with a scope looking for that odd shaped ripple on the rails quickly enough), but if a second one went short then the transformer would have a high current flow in the winding, and would gradually heat up.

As the unit was hermetic, this meant no smoke or flame, just a transformer making toxic fumes and eventually getting hot enough internally to destroy the interwinding insulation, typically after dumping a load of liquid melted thermoplastic and varnish byproducts into the case and into the cooling fan. Only then would the primary current be high enough to blow 2 of the 3 1A solder in fuses that provided protection, and the built in test light relay would drop out and show a fail on the master caution panel. I did order some spare power supplies, and I guess Fraser would know the route they took to get there, along with the price of them. Never seen that many digits in an invoice before, for something that was basically fist size, and which I guess was about the price of Promethium per gram, as it was a lot more than Gold, Platinum, Palladium or Rhodium..

Back in the day, I worked on a Pye  UHF TV Transmitter which used stupidly under rated EHT rectifiers.
These things would blow if you looked sideways at them.
Getting replacements from the UK took forever--a fast (hell, no) a slow windjammer would have beaten their best efforts.
Dunno how much they cost, wasn't my department.
Meanwhile, NEC used over rated rectifiers which lasted for decades.

Later, in another job, we had  mainly Sony picture Monitors, but also a few Barco ones.
Sony parts availability was generally overnight, whereas you could probably budget a month or more for Barco.
I think some European companies "piggy-backed" their packages on someone else's container, which didn't move until it was full.

[IAmBack]

Adjustable 15A 25V bench PSU unit that "stucked" on 13.8V was bought by me in a fraction of price. Problem? Switch on the bottom of the unit that sets constant voltage to 13.8V was turned on. So... RTFM.

[Arek_R]

Adjustable 15A 25V bench PSU unit that "stucked" on 13.8V was bought by me in a fraction of price. Problem? Switch on the bottom of the unit that sets constant voltage to 13.8V was turned on. So... RTFM.

What kind of PSU has switch for such a weird value?

[helius]

What kind of PSU has switch for such a weird value?

One intended for float charging lead-acid batteries, or operating mobile radio equipment at 13.8V, said equipment designed for the output of a vehicle's alternator. You also sometimes see 14.4V which is for equalizing lead-acid batteries.

[IAmBack]

Adjustable 15A 25V bench PSU unit that "stucked" on 13.8V was bought by me in a fraction of price. Problem? Switch on the bottom of the unit that sets constant voltage to 13.8V was turned on. So... RTFM.

What kind of PSU has switch for such a weird value?

It is Voltcraft 25A/15V psu. 13.8V is probably intended for automotive applications.

[CJay]

HP Laptops have a really annoying 'feature', I've seen it on a hand ful now (I've processed over 1000 in the last 12 months) where the machine refuses to turn on.

Press and hold the power button for 15 seconds, then release, then switch on as normal.

[Stavos122]

Blown fuse in an Omega Engineering meter https://www.omega.com/pptst/HH314A.html  Saved a couple hundred.

[EE-digger]

Brought a half brain-dead, new to me 33120A Arb to life by momentarily shorting the PONRST line to +5V a few times with a scope probe.  I think this opened up a bad cap.  Details in the old 33120A thread.

[peteb2]

How's about a piece of Hi-End audio production suite monitoring-mixing bridge technology that enables the operator to verify audio levels across multiple stereo (on a group of LED dot bar 'VU' meters) embedded tracks and and to even decode the 'stream' to inbuilt speakers or use headphones.

The user called said the audio sound had stopped and it had been flaky for a few days. The had a something else installed, temporarily  but it wasn't  as good and were desperate for this one to be looked at. It arrived with user and the brief was that it had been a bit scratchy recently, a month ago but now it was dead but the VUs still worked fine.

So i looked at the front of the thing having never really seen one before and right beside the centrally marked VOLUME knob in a sea of push buttons and silk-screened labels was a jack socket labeled (headphone Logo)/MUTE... That's when i did a double take on the 1/4" socket and pulled out the 1/8"(3mm) headphone adapter that whomever was the last operator using Cans had left behind....

YEAH..... and you should have seen the look of the individual who'd spent the better part of a morning uninstalling, reinstalling and traveling on a mission of urgency....

I wonder too, how often do headphone 6.35mm to 3mm adapters cause mistakes like this?

[station240]

Visiting my friend many years ago, they had a massive CRT TV, like 80cm size, that didn't work anymore.
Everyone was watching it when it stopped working with a loud bang and sparks coming out the back.

They wanted it gone, so I took it home opened it up. No signs of problems around the mains section, however the module with the EHT was another story.
Undid a couple of screws to pull it out, flipped it over the see the back. Not only is there a EHT cable to the tube, but a secondary one runs into a finger sized 10meg ohm resistor, with a huge crack up the side.

The fix, pull the rubber boot back, unscrew the screw inside the port securing it, chop the EHT cable off the dead resistor, refit boot minus cable.
Voila set works again, resistor was only to discharge the tube when the set was off.

[iaso]

I had a 2010 Macbook Air. It had some screen issues. Apple quoted some ridiculous ammount for a fix. I opted out of that scam and basically decided to just buy a non-apple product.

On the way home I accidently dropped it.

It fixed the screen issues, worked fine for 4 years after that.

[rrinker]

For the computer builders here: did you ever have the experience that your friend's computer went dead, they couldn't fix it, and the computer magically fixes itself after you show up?

 All the time. It's my regular job to fix computer systems, more server side stuff, we rarely do deskside support any more, but even there, the same thing happens. Just called a client yesterday, he goes to demonstrate the issue he is experiencing - and everything works perfectly as it should, no errors.

 When it happens with a friend or coworker, I jsut say that the computer is smarter than they think and is afraid that I will resort to percussive maintenance. 

[jmelson]

OK, here's a funny one.  I have a home environmental monitoring system, that is cobbled together with all sorts of adapters, interfaces, etc. to a rack-mount  1976-vintage analog-digital converter.  It all works, mostly, but now needs a fan on it in the summer or you get wildly fluctuating readings.  (It measures outdoor and indoor temperature and humidity, electrical power consumption, furnace activity, etc.)  Well, a while ago it started acting flaky again.  I shut it down and pulled and reseated all the cards, cables, etc. and it still seemed to be malfunctioning.  The outdoor temps seemed too low.  After fretting with it for quite a while, I finally looked up the weather online.  Yes, a front had come through, and it really WAS 3C outdoors!  I think a connector was making a bad contact, and reseating fixed that, but then I didn't believe the readings, and spend another hour fooling with it when it was NOW working properly!

Jon