What was your easiest repair ever?

[vk6zgo]

Back in the '70s----little "El Cheapo" AM CB radio from K-Mart.

It put out the full "humungeous" 4 watts,but nobody could hear me.
Took it to work.looked at it with the CRO---It was making about 1% modulation.
Opening it up,I found that the 0.47uF coupling cap in the mic amp was actually 0.0047uF!
On replacing it with the correct value,all was well.

Interestingly,the schematic in the "Owner's Manual"* said 0.47uF,but the Parts List (BOM to the children) said 0.0047uF.

No guess which the assembler worked from!

*Oh for the days when a $25 purchase had a Manual with a schematic!!

[bitseeker]

Reflowed it with extra solder and Bob's your uncle, problem solved. 5 minute job. I wish it was always this simple.

Yeah, tell me about it. Had some decade boxes with bad solder, too. If only everything was so easy.

[TerraHertz]

Today, a friend brought round a nice Xeon server PC he'd scored free. Junked due to 'no power up'.
Coin cell flat, replace, still no power up. (Some PCs, if the cell is dead the motherboard won't signal the PS to start.)
Checked power supply: P_ON# line does nothing, and +5V_Standby is 2V. Opened supply, after some quick checks (Fuse OK, HV DC OK, main transistors seem OK) noticed two small electros in the standby supply had domed-out tops. Replaced them (two 1000uF 16V) and now the PC works. He's happy, and so am I since that's a favor returned.

[SeanB]

Funny enough, a Hoover branded bagless cyclone cleaner, which was full of dust, and where the cyclone was packed solid with dust and carpet fur as well.  The flat pleated filter was a flat surface on the inlet side from dust. A few wash cycles and some digging out of the kilo of felting inside the housing, and a good drying and it now sucks quite well, though it is incredibly noisy, compared to the other canister vacuums I have.

Possibly noisy because the motor may be damaged, when there's lower air pressure the motor will overspeed and may damage bearings if left for any length of time.

They are all noisy, just because of the lower cost manufacture, so they do not put in any sound dampening foam or anything like an outlet filter. If it does die I can get the whole motor assembly cheap enough though, around $ 25, and fix it. Amazing how many assorted vacuum cleaners use the same 5 different motor assemblies inside, with most being covered by 2 only, a single and a double stage pump and motor. Same motor assembly in the $30 unit as in the $200 unit, just the one has a fancier case, more foam damping and 2 extra filters and a flashier external casing.

In any case the motors are all made now with CCA wire and with the design voltage being 200VAC, which means a shorter life on our standard 230VAC mains, though with the thin power cords that are used the motor will probably run at 200VAC in any case, with 30VAC drop along the cord in the steel strands.

Currently local mains is 234.2VAC, though it vcan be as high as 239VAC, and I lived in an area which still has the original transformers from 1910 in service, where the whole district had mains that ranged from 235VAC at lowest to 255VAC at highest, as the original standard in South Africa was 250VAC mains, later harmonised to 240VAC and finally to 230VAC. Made for great heating, but a really short lamp life.

[Koray]

Great thread! I hunt for broken stuff on ebay all the time!

My easiest repair was a corroded battery cover on a brand-new condition Metz MZ54 professional camera flash unit. Just a puff of contact cleaner and it came to life.

Another find led to a goldmine for me actually. Fujifilm F30-F31fd cameras had an inherent problem with the battery door not latching in properly, leading to door sensing switch staying open. Finding out the problem I scored many of them, repaired and resold for easy money for a year or so.  Similarly, I  managed to fix many Canon EOS cameras with blown SMD fuses, another goldmine.

Again, I once scored a faulty Denon RCD-M39DAB unit, having issues with some buttons on the front panel. While I was expecting to dig in microprocessors and all, it turned out to be a cracked single sided PCB. Apparently someone knocked on the volume knob and cracked it! A few jumper files, and it was all set. 

Oh and there was this Sony BTX500, which I repaired by the help of the crowd here, where the thing came to life when I was poking with a multimeter. A jumper cable was all that was needed.

These are only a few that I can think of...



Koray

[Samogon]

Keithley voltage source 230,
Got for $112 as not working, on the back there is input voltage markings ticked 220V but 110V was painted over so i assumed that this was used as 110 but then tranformer fried.
Opened case flipped 110/220 switch and I have fully functional unit.
Of course cleaning and some case fixes with epoxy.

[pelule]

Got an HP 419A as "for parts only", paid $21 including shipment. Defekt: the power cable was broken.
PeLuLe

[Skimask]

Worked at a fixit shop while in the USAF.
Guy moves from England back to the U.S.  Walks in with an audio amplifier.  Says it doesn't work and he's been to 3 shops already with no luck.  Says he'll buy the whole shop lunch for a week if we can fix it.  Sets the unit down on the desk with the rear facing me. Without miswing a beat, I reached over, flipped the 120/220 switch, and asked him if he had a van or a bus to haul us all to lunch.

[smugtronix]

Not mine, but for a friend:
1974 Ampeg V4 guitar amp that he picked up for $200, the only piece of information I had was "It doesn't turn on". Surprise surprise, it was a blown fuse. I still rebuilt a majority of the power supply (These amps run insanely hot, and a bunch of the carbon film resistors in the bias supply had drifted way out of spec, so I replaced those to hopefully cut down on the noise). Easily one of the loudest amps I've ever heard, and thankfully none of the tubes have gone microphonic, it costs a small fortune to fully retube one. 

[sonicyang]

Got one HP54600A with popped cap in CRT assembly.
The cap is easily accessible, I don't even need to take the board out of the frame.

Replaced, and become working for another 3 years till now.

[PaulAm]

I bought a Fluke 332b voltage standard for cheap sold as non-working - no output voltage.

The voltage-trip control which disables the output when the voltage exceeds the setpoint on the front panel was set at 0V.  Turned the knob to the right and I had a completely functional 332b.

I recently picked up a Tektronix 1502 TDR marked as totally fried.  I opened it up, reattached two hanging cables and it worked fine off of a power supply.  That one still needs a battery pack.  That was easy, but not quite the same as the 332b.

[calmtron]

HP 5334A Universal Counter, sold with the description "Powers up but does not respond to input". Turned it around and toggled the timebase selector switch on the backside from external to internal - fixed!

[Smith]

To name just a few:

Expensive Marants cd player for next to nothing because the laser was bad. Just blew the dust off the laser, and after >10 years it still works as my daily cd player.

Onkyo surround amp for 10 bucks (with HDMI, usb support etc) for 12 bucks. Jumpwired the thermal fuse of the transformer, all is fine.

Keithley 199 wich was bad (and free). Cal was gone because of empty eeprom. Just calibrated it, still works fine.

[Kjelt]

Onkyo surround amp for 10 bucks (with HDMI, usb support etc) for 12 bucks. Jumpwired the thermal fuse of the transformer, all is fine.

Rather place a new thermal fuse against or better in the transformer, you never know .

[bitseeker]

Turned the knob to the right and I had a completely functional 332b.

That's excellent!

[retrolefty]

Easiest repair I read about was in the air force. Repair write up on a specific pilot complaint stated no problem found, suspect intermittent short between the headsets. 

[RobertHolcombe]

Not a repair, but...

My family bought a no name brand LCD TV in the mid 2000s and it worked for a while but eventually the sound stopped working. We took it back to the store to exchange it but had to first have them test it to determine if it was in fact faulty. They plugged the power in but the TV didn't turn on from the power button or remote    We and the staff were both puzzled... turned out there was a power rocker switch on the bottom edge of the display which was conveniently placed where a person would hold the unit while picking it up.

[Chris Mr]

16 x USB MIDI music keyboards from a local school

Every one had the USB socket broken on the PCB - you couldn't tell from the outside

4 screws out, change the socket, 4 screws in

They were delighted 

[charlespax]

My 12" MacBook was having some sort of RAM problem. After running for a bit the system would halt and display an error message. I removed the RAM module and got the same issue with using only the RAM soldered to the motherboard. I desoldered and lifted the power pins on the onboard RAM chips and got the system running on just the RAM module. Not a complete fix, but it got things working again.

[tautech]

Charles reminded me of a Toshiba Satellite 200 laptop with a Bios driven integral fingerprint reader as the default system login and it wouldn't/couldn't boot. 
A bit of Google'ing discovered that early bios versions would without reason enable the fingerprint reader and effectively render the laptop useless. 
Online comments were of the order: it will lock you out but who knows when.
Further Google studies found the "secret" reset contacts under the ram modules and with those momentarily bridged with the power button simultaneously pressed and tongue held at correct angle the Bios could be reset. 
Upgrade Bios to later version....fixed.

Supposedly several "experts" had attempted to "crack" this laptop and it was given up as lost  and I still use it occasionally today.

[BMack]

One of my shop techs bought a "Non-working" bluetooth speaker from a pawn shop for $1. He decided it was worth a shot trying to fix it but he's been busy lately so it's just been sitting on his bench for the past month. I ran out of stuff to do today, just waiting on parts, so I decided to take a look at it. I push the power button, nothing. I hold the power button down for 3 seconds, it turns on. I pair it to my phone and bring it to him playing music. 

[iXod]

50 in Samsung DLP 1080p TV. Rescued it from scrap heap. It would turn off pretty regularly after warming up for maybe a half hour. I did a net search on the symptom, turned out that the door on the back that gives access to the lamp has a microswitch that goes high-R. I cut and soldered together the switch's wires. A friend gave me a Sam remote. It's been working well ever since (3 years). None of those flat-panel failures (lines, etc.). Great picture.

[EduardoLM]

Perhaps not so easy, but with great value for me!

Some time ago a friend gave me one of those Hantek USB scopes (DSO-2150), that used to work for some weeks, then stopped working. He got pissed of it, after he tried to fix it by replacing one of the TSSOP A/D chips, but he ruined one of the part tiny legs.

I have managed to use a Dremel to excavate the tiny TSSOP epoxi and bridge the missing pin back into place, but that didn't fix the main fault. I noticed that by flexing and pressing the board, the scope would work, but it stopped working as soon as the pressure was removed.

So I got my magnifying lens and started checking each IC pin, and found the main FPGA with missing solder on one pin. Ressoldered it, and the thing got back to business, rock solid, never failed again!

Later I sold this unit and used the money to buy my first real scope, a Tektronix TDS-1001C, which is not great, but much, much better than that Hantek USB thingy.

Eduardo

[Assafl]

Interestingly,the schematic in the "Owner's Manual"* said 0.47uF,but the Parts List (BOM to the children) said 0.0047uF.

*Oh for the days when a $25 purchase had a Manual with a schematic!!

I always wondered what happened with the schematics for household electronics. An older shop owner enlightened me with a reasonable explanation - that in the old days, tube equipment always had schematics since tubes would burn out and need replacement - even by users (in those days rummaging in high voltage equipment was considered ok for lay users - until politicians learned that policing electronics is power); as the evolution to solid state was happening, manufacturers would still give away schematics - since it was what they did.

Replacing a transistor (let alone and IC or worse - SMD) is far more trouble to plugging in a tube - so over time, the schematics got relegated to service manuals for professional use only (with lots of legal waivers, warnings and cautions etc.), and today, having realized that replacing boards is far more lucrative than fixing them - made the schematics disappear forever for many a household product - how unfortunate.

OT: I have been playing with electronics since 1981 or so. In those days noisy pots were the easiest fix - contact cleaner would restore any Marantz (including my parent's) to former glory.

[HighVoltage]

When I grew up in Germany in the 70s and took my first TV sets apart, they all had full schematics in a special side bag inside the TV. And these schematics even had scope pictures in them.
One can only imagine, how much work that was to produce them by hand.

Those days started to fade away already in the mid 80s in Germany.