What was your easiest repair ever?

[rhb]

I got a wonky eBay 34401A.  Connected to a 5.0 VDC reference it just showed random digits on the mVDC range.

Opened it up and took off the internal shield.  I found flux painted all over one of the LF357s in a 1 cm spot.  I cleaned it off with isopropyl alcohol and a soft brush.  It now reads to the accuracy of a DMMCheck Plus which was calibrated to 1 ppm a few weeks ago.

The flux was so thick I couldn't read the chip markings. On close examination after cleaning the part was a different make and not quite aligned straight.  It had been repaired by a slob.

Rosin is hygroscopic.  In a humid environment this creates stray capacitance and resistances that play hell with low level signals.  Wash it off!

I've made similar repairs to a variety of consumer electronics devices.  The hardest part is taking the stuff apart to clean it.

[innkeeper]

Saw this topic and had to post cause it reminded me of one of the first repairs I did for someone else other than me and one of the easiest

this goes back some 35+ years ago....my brother was wanting a stereo system, but, was strapped for cash.  I brought him to a Macy's discount center where the would blow out returns and broken times, and sell off old models. There we found a complete Technics's component stereo system, with turntable, speakers, and cabinet....but one channel was out.

When I moved the speaker and I could hear a loose wire moving inside. the sales guy was hovering over us, so all i could really tell my brother was to buy it I can fix it. My brother paid very little for the setup... and we loaded it into the car, .. my brother being skeptical he was already regretting the purchase, until we got home, hooked it up, I unscrewed the woofer and reconnected the loose wire to the terminal and watched his amazed face.

I can remember feeling good about being a hero to my little brother...35 years later, he still has the system.

[CoopedUp]

 I got a nice hd 27" monitor from a business because they said it was faulty... When I got home I plugged it in to see what the problem was, and everything was green so I figured I would try the color settings and sure enough it got switched to the all green mode and I put it in rgb and boom free monitor.

[vk6zgo]

I think I've mentioned this one before, but here goes:-

An Icom IC 910 transceiver made "clicking" noises, & after a short time would overheat & drop in output power.
A misplaced ribbon cable was preventing the fan turning.
Redressed the cable, & all OK.

[digsys]

My last "easiest repair" was several weeks ago. I was called out to a intermittently operating plastics injection machine. I was warned that several service /
 techs had already had a look at it, and failed to find the fault. I asked for pix of the electronics to be sent, to get an idea of what I was up against.
It was a mess. A very old machine, heaps of PCBs, relays, connections, wiring etc etc. So I grabbed everything and went down.
Unloaded my car, oscilloscopes, DVMs, current sensors, heaps of parts drawers plus my trusty E8 errr I mean E4 FLIR.
Set it all up, opened the main cabinet door, whipped out the FLIR, had a quick scan ... and right there, in the middle of a huge row of terminals, saw one was
extremely hot !! Had a look - the screw was completely loose, and the eyelets were just flapping inside. Totally impossible to see with a naked eye.
I tightened the screw, and BINGO, all fixed.
Worst was reloading all the damn stuff back in the car, and putting it all back at the office.

[vk6zgo]

A mate of mine was asked by his Boss to produce a counter which would give a tally of how many times a
particular operation occurred.

It didn't have to interface with anything, so he grabbed a cheap pocket calculator, set it to increment the
reading by 1 every time the "+" button was pushed.

He then found a spot for a micro switch, wired it across the "+" button & it was done!

No microprocessor &  peripherals, just a switch & an "El Cheapo" chain store calculator.
(No PICs or Arduinos back then!)

[Rerouter]

vk6zgo, you can get little self powered increment / decrement counters with an LCD for dirt cheap if you know where to look,

e.g. https://www.fargocontrols.com/spcounter.html

Thoughts for next time, I have a few of these I have kept on hand, the battery has only discharged about 30% over 4 years of use, and they never turn there screen off.

[kripton2035]

non working inverter came into the shop. dead on arrival. called the manufacturer that managed a replacement.
then they left it "to disposal according to your country laws" ... so I opened it. battery was not plugged in ...

[vk6zgo]

 

vk6zgo, you can get little self powered increment / decrement counters with an LCD for dirt cheap if you know where to look,

Indeed, but this was 40 years ago!(Note the last sentence of my posting.)

e.g. https://www.fargocontrols.com/spcounter.html

Thoughts for next time, I have a few of these I have kept on hand, the battery has only discharged about 30% over 4 years of use, and they never turn there screen off.

Still good to know, but these days, the Boss would be a "suit",who would want the counter to upload to "the Cloud"!

[vk6zgo]

non working inverter came into the shop. dead on arrival. called the manufacturer that managed a replacement.
then they left it "to disposal according to your country laws"... so I opened it. battery was not plugged in ...

Not quite on topic, but fits in well with your story.

Back in the '60s, a lot of farmers weren't on the grid &  had 32v DC power plants.
Nobody made TVs to work on that supply, so they bought electromechanical inverters which used a very much "scaled up" version of the "vibrator" supplies used in old style car radios.

A country customer came in, wanting to buy one while he was in Perth, but when the counter attendant went to grab one from the store,"the cupboard was bare".

The counter bloke's eyes fell upon the one on display.
Sure enough, the exact thing, & the box was even there.

The sale was made, the customer went away happy, all was flowers & unicorns, till the Boss noted the counter display unit wasn't there.

You guessed it!
The counter one was a dummy with no active guts, just a few weights to stop it being easily nudged off the counter.

Luckily the Boss knew the customer well, so could make a good guess where he would go next, & "headed him off" before he set off for home.
Meantime, us lesser mortals were sent on a hunt to find an inverter "by hook or by crook"!

From memory, one of the country branches had one, which was quickly shipped prepaid to the customer's business address.

[madao]

my most (& fresh) easiest repair is  turbo boost sensor from my nissan Skyline.   bad solder, required resoldering.   I needed more time for extending of him than soldering.

Other one easiest repair:  I picked up Tek  533A  Oscilloscope for friends. Seller  switched him on  and i play. Trigger doesn't working.
  I pull it out case and saw a tube with white hat.   Of coruse, it is in trigger-ciruit.  Put one new tube - > problem solved.

[LapTop006]

Probably not quite my easiest after all the "actually worked fine" and "flip the power/input switches correctly" ones, but one of the most satisfying was a Keysight N6700 power supply mainframe.

Bought as "powers up dead" for an extremely cheap price I confirmed that when it arrived, took it a little to bits, didn't find anything, reassembled, and it worked fine.

Despite being new enough to be Keysight branded the firmware is all-Agilent, all the way.

[bitseeker]

Bought as "powers up dead"

That's a new oxymoron.

[innkeeper]

Probably not quite my easiest after all the "actually worked fine" and "flip the power/input switches correctly" ones, but one of the most satisfying was a Keysight N6700 power supply mainframe.

I had a quite satisfying "actually worked fine" one that happened quite recently. ..

I picked up this Tektronix 576 curve tracer that originally it was listed along with with a Tektronix 2465B 400 mhz 4 channel scope, both showing no trace, and listed on ebay "for parts" no returns. I figured they would be fun projects, so I gave an offer on eBay that was accepted. 

I drove 2 hours into NJ to an electronics salvage warehouse to pick them up only to find out they "goofed" on the listing and the scope listed in the title and in pictures was a "mistake" ... grrr .. well it seemed they weren't about to let me walk out with both the scope and the curve tracer... at least not for the price I paid. they wanted like +400 for the scope.  I felt that was very sleazy.

They kept offering me to come to the back look at other things to buy while I was there, it felt a lot like a bait and switch thing.

I ended up negotiating and refund on the scope that was in the listing and walked out with the "non-functional" curve tracer .... at that moment, I felt like I had been dupped...but on the other hand, was not upset at the deal on the curve tracer as a project piece.
 
However ... Karma is a wonderful thing...

It turns out that the curve tracer works fine, they just had no clue how to use it ..... 

[widlokm]

Not mine repair, but I've red this story long time ago on some clocks forum. Not the easiest one also.

In the past companies used "time systems" with one big "master clock" and many "slaves" connected to it by wires and triggered every minute to advance. Company claim was that some part of the system losses a few minutes every Monday, Wednesday and Friday. Clock engineers narrowed the problem to a particular "impulse amplifier" (electro-mechanical, just switches and relays), check it, found some dirty contacts, concluded that the week days was just an coincidence, repaired and ... that NOT fixed the problem. Then they simply replace the whole amplifier module - still no luck. In the last attempt they decided to do 24h watch of the falling unit in shifts.
The problem was fixed the next day: a person who watched the unit at night noticed that a some point a cleaning lady came in to the room, unplugged the amplifier and plugged in hers vacuum cleaner. After a few minutes of work she took a vacuum cleaner, plug back the amplifier and left the room. Cleaning was done on Mondays, Wednesdays and Fridays :-).

[vk6zgo]

A new low!

One of the charger cradles for our Uniden cordless phone had "croaked".
We only had one functional cordless phone, which needed to be in one particular room, so we needed to take it to the base unit in another room to charge it overnight.(couldn't just swap phones for a charged one)

After bring out of action for some time, following a Total Knee Replacement, I finally ventured out into the "Ham shack"/Lab, grabbed the Fluke 77, & did the simple checks.
No output from the charger!

Looked in the "computer junk" for a compatible charger.

Bingo!
The "charger" from our previous ADSL box was compatible---- even the same centre pin on the barrel connector.

The cradle returned to service.

You couldn't get any easier than that!

[Smith]

I bought a like new 1/10 LRP S10 Blast RC car this weekend at a local thrift store for 7,50, including remote and a good battery pack . It was untested, propably because there was no charger.

Charged it up, it would steer hard left. Inverting the steering made it steer hard right. Turned out one wire from the steering pot from the remote was not soldered propperly, and had come loose. Easy fix.

[briandorey]

I was given a bang & olufsen amp for spares which I was told was completly dead and their technician couldnt fix it, turned out to be a 50p fuse !

[GreyWoolfe]

I was sent 3 document scanners that we use in the field as non working to see if I could do anything with.  The easy fix was a jammed light bar.  Moving it back and forth a couple of times made it work.  It took more time to remove the 3 screws, undo 2 connectors and remove one cable than it did to make it work.  The other 2, unfortunately, were FUBAR'd.  How they could be dropped hard enough to shear the 3 mounting posts for the drive motor and not leave a mark on the outer case is interesting. I will be keeping one as a parts carcass, it already gave up its ADF tray for my office scanner.

[Psi]

I bought a faulty argon ion laser with powersupply for $20 because i wanted the large toroidal transformer that came with it.

I get it home and figure i will just plug it in to the wall to see what happens.  Fans power on and tube glows but no laser light.
I tap the mirror at one end of the laser tube and i get a flash of 488nm light.

So i grab an insulated screwdriver and turn the back mirror X adjustment screw about 4 degrees to the left.

Wow! laser fixed.

Damn it, i can't really rip it apart now that it works. And I really wanted that transformer. 

[dom0]

Tektronix 2246 that didn't trigger properly. I kinda didn't need it, bought it more for completionist/collecting stuff reasons. And it indeed didn't trigger reliably. So I just stashed it in my storage a couple years ago. Thought two hours ago, "hmm, I didn't use that 224-something in years!".

Works flawlessly. Quite a nice scope, too. (I should probably open it up and check there aren't any obvious issues inside)

[bob91343]

I have several.  One was an Astron power supply that had no output and was given to me by a ham radio operator in hopes I could use it after repair.  It has three terminals on the rear, positive, negative, and ground.  He had connected the load from ground to positive and it was a floating output so of course zero volts.

Another was a printer that I got from Craigslist.  It kept giving a paper out error message.  I merely corrected the positioning of the paper guide and all worked well.

[bob91343]

I have two units, a Tektronix oscilloscope and an HP bench DMM that have had bad power switches.  The previous owner of the DMM had bypassed the switch so he then had to use the power cord or a power strip as a switch.  The oscilloscope was a freebie at a swap meet; the power switch is buried so deeply I see why he didn't replace it.

In both cases I just exercised the switches and after a few times they became reliable.  Haven't had a problem since.

In another situation on a first date I was asked to wait until she finished getting ready.  The stereo was too loud so I tried to turn it down and found it cut out.  So I exercised the slide control until it started to work properly.  When she came out I told her I turned the stereo down and she said oh it's broken you can't turn it down.  Then she moved the knob and said what did you do?  It's fixed!

[ArthurDent]

I bought a FEI-Zyfer 565 GPS time and frequency system that was dead on eBay. The seller plugged it in, turned it on and there was no display or beeps when the buttons were pressed. I had several older 365 that looked the same and figured I might be able to figure out how to upgrade mine to this much more desirable and newer model so it was worth chancing the $60-75 to buy it.

When I received it, it was dead as described, but when I continually pressed the contrast button (see photo) the display came to life. I could then go through the menu and turn on the beep function for key press. There was nothing wrong with it except it was set up wrong. The main board was identical to the 365 model I had so replacing the old small GPS receiver board and an eprom upgraded all my other 365 units.

[eevcandies]

In the mid 70's the first scientific calculators were at least $300, and being a school kid, no chance at all of having one.  I found one--a store had a defective one that was returned because it always gave wrong answers...So I was able to buy it for $20.  I thought it was very very cool to have, even if the calculations were wrong.   A few months later I was messing with it & noticed that when I took the log of 36 I got 6.  When I  took the square root of 90 I got 1.000,  The square of 100 was reported as 2.  I suddenly realized most of the function keytops had been scrambled around.  I opened the unit & figured out where the keys should go.  Soon thereafter I had a fully functioning calculator.