Author Topic: What was your easiest repair ever?  (Read 62333 times)

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Offline Assafl

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Re: What was your easiest repair ever?
« Reply #75 on: July 19, 2016, 09:23:51 am »
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 bad 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.

You know this trend was limited to household stuff. I got a SMEG professional (restaurant) dishwasher and was surprised that it had full diagrams (blocks diagram wiring - not schematics) under the footboard. Mitsubishi air-conditioner still has one as well (and service manuals online).

But unfortunately, home stuff does not. E.g. trying to get a Gaggenau diagram from BSH requires a real bribe. Miele is even worse. Unfortunate since neither has service of any quality (or even mildly knowledgeable) outside Germany and some big cities like New York. In Israel BSH and Miele are awful.
 

Offline CJay

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Re: What was your easiest repair ever?
« Reply #76 on: July 19, 2016, 09:54:23 am »
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.

Oh I remember those, Grundig televisions were pretty much the only German sets I ever worked on but those schematics were excellent.

We used to get 'first issue' service manuals for Philips equipment for free but you had to be a dealer to order them.

All those 4822 numbers...
 

Offline HighVoltage

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Re: What was your easiest repair ever?
« Reply #77 on: July 19, 2016, 10:10:11 am »
Yes, you are right!
Grundig had by far the best schematics around and they were printed in color!
And for the big TV sets, they filled a table in size.
I should have kept one, just for fun.
There are 3 kinds of people in this world, those who can count and those who can not.
 

Offline CJay

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Re: What was your easiest repair ever?
« Reply #78 on: July 19, 2016, 10:41:13 am »
Yes, you are right!
Grundig had by far the best schematics around and they were printed in color!
And for the big TV sets, they filled a table in size.
I should have kept one, just for fun.

I've probably got one somewhere, lurking in an old box of Television magazines, I know I have a few of the alignment trimmers they used to include inside the sets and I still use them to this day.
 

Offline alterbaron

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Re: What was your easiest repair ever?
« Reply #79 on: July 20, 2016, 02:00:34 am »
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!
 

Offline KeepItSimpleStupid

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Re: What was your easiest repair ever?
« Reply #80 on: July 22, 2016, 06:40:36 am »
Car clock:  Jumped car.  Clocked died.  tried to find replacement clock $400.00 USD. Unhooked car battery.  Shorted battery terminals toward car for a few minutes.  Fixed.  Lots of things fixed that way.

Recent ebay Keithley 485 with IEEE cheap <$100.00 USD.  Cut power cord.  Crack in the case.  Put it into another case temporarily and set he voltage switch right.  No issues.  I ordered parts to replace the cord and the feet.  Glued the crack.

Two other 485's broken.  Bad FET. $6.00.  I can't find the FETS I used to fix the K485, but another seemed to suffer the same fate.  Troubleshooting takes about 10 minutes.  So, two now need calibration.

I would not call the next repairs easy, but they were straightforward.  A 13 kV  1.5A power supply for an e-beam kept blowing the same transistor about every 6 months.  My predcessor just replaced the transistor.
I replaced the transistor,  a 1 Meg 200 W bleeder and some 625K resistors in the voltage divider and got out my bottle of Locktite 222 and tightened every electrical connection possible.  Did that on a 100 kV 0.1 A X-ray supply too after replacing a few components.  We had bought a 3-source e-beam evaporator at auction for like $45,000 USD.  Instead of removing the connectors, they cut all of the wires a few inches from a terminal strip.  The connectors were hidden - I'll give it that.  the HV wires were also cut.  You just had to remove 3 screws.  Methodically, it went back together SLOWLY.  Locktite to the rescue again and tthe HV regulator tube popped out of the socket.

RS232 driver kept blowing on a Databox (An after-market goniometer automation gadget).  Isolated the RS232 lines.

The 10 A rectifier where a 50 A should be,  That was super easy.  Yell at the manufacturer (we had a good relationship) and they fixed it for free (new transformer and new rectifier with a new design).

The HVAC guy at our place decided that the air to water heat pump in the ceiling was bad, so he ordered another and had it installed in the ceiling.  He could not get it to work.  I gave him about 10 minutes of my time and said replace the t-stat wire after he did some measurements under my direction.  During a re-model the t-stat wire got caught on a metal stud.

A Keithley 4 quadrant source.  I'd have to find the number. Wrote a  program to exercise the OUTPUT ON relay overnight.  Fixed  the next morning.

An impatient neighbor called me that her cable box wasn't working.  The all-in-one remote was toggling the TV on and the cable box off etc.  So much for dedicated ON/OFF commands.  Checked IR LED with cell camera.  Got them in sync and replaced the batteries in the remote.  I suspect that the sensitivities of the cable box and the TV were different.

Same neighbor called me and the box was showing some sort of crypic error.  She doens't know about capacitive buttons and the box was unresponsive to the power button.   Unplugged it to re-boot.  In the meantime she's trying to call the cable company. Basically let them guide me.

« Last Edit: July 22, 2016, 06:57:53 am by KeepItSimpleStupid »
 

Offline CJay

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Re: What was your easiest repair ever?
« Reply #81 on: July 22, 2016, 07:02:24 am »
A Keithley 4 quadrant source.  I'd have to find the number. Wrote a  program to exercise the OUTPUT ON relay overnight.  Fixed  the next morning.

Was told a story by an ex colleague of mine, he worked at ICL in Cheshire back in the day when we Brits made computers.

One of his colleagues developed a test rig for the pneumatic valves used in tape units for the (I *think*) ICL 2900 mainframes, said test rig would exercise the valves and help eliminate failures.

Sadly for him, the rig didn't take into account the lifespan of the valves and after a weekend long run he came into the workshop to find several thousand pounds sterling of wrecked pneumatic valves.
 

Offline KeepItSimpleStupid

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Re: What was your easiest repair ever?
« Reply #82 on: July 22, 2016, 07:31:03 am »
I hate it when you buy brand new valves (24 VAC coils) and you have to take them all apart and clean them to get rid of the dust or they hum.  Today, I re-built 3 natural gas manual valves.  Not as fun as much fun as rebuilding  a carb.

Or brand new wafer probe needles can't be used at high T unless you boil them in baking soda and electroless gold plate them.

Then i really hate when the manufacturer changes from brazing to 60/40 solder and the needles fall off.  Fortunately, they were able to use Sn96 for us.

 

Offline LazyJack

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Re: What was your easiest repair ever?
« Reply #83 on: September 22, 2016, 07:52:13 pm »
This baby was on eBay for a long time. Advertised as being in the notorious "Powers up, not tested" sate. The picture there showed indeed nonsensical display, with conflicting lights and missing segments. But, as this was the military version, with GPIB and oven oscillator it was bugging me to get it. So finally took a chance, as it was cheap.
First try, it did exactly what was shown on the picture, garbled display, no reaction to the buttons. I checked voltages, the -5.2V supply was 0.5 instead. Strange. Pull the GPIB board first. Nothing. Pull the Channel C prescaler board, it works! Check the obvious for shorted caps etc. on the prescaler. Nothing. Put it back, it still works! Very strange.
Put everything together, still works and has been ticking on my desk now for a couple of hours.

I have no idea what was causing this, could have either been some short, like a solder blob or something touching something else, which fixed the issue. Only thing to fix is the small fuse inside the Channel C BNC, it's blown, needs replacing, but bypassing it showed that Channel C works.

Extra bonus: all the buttons work fine, even though this model is known for the buttons failing.
So this repair was quite easy, take it apart and put it back together.
 

Offline Jeff_Birt

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Re: What was your easiest repair ever?
« Reply #84 on: September 22, 2016, 08:05:42 pm »
I filled out a 20 or so page PO request, had a background check, drove 5.5 hours one way, went through security at a nuclear power plant, and flipped a switch on a plasma cutting power supply.
 

Offline GreyWoolfe

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Re: What was your easiest repair ever?
« Reply #85 on: September 22, 2016, 09:26:25 pm »
I filled out a 20 or so page PO request, had a background check, drove 5.5 hours one way, went through security at a nuclear power plant, and flipped a switch on a plasma cutting power supply.

 |O |O :palm: :palm:
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Offline bitseeker

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Re: What was your easiest repair ever?
« Reply #86 on: September 22, 2016, 09:42:48 pm »
Put it back, it still works! Very strange.
Put everything together, still works and has been ticking on my desk now for a couple of hours.

Very strange, indeed, but what a score. It is somewhat rare to get one with all good buttons.
TEA is the way. | TEA Time channel
 

Offline whitevamp

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Re: What was your easiest repair ever?
« Reply #87 on: September 22, 2016, 10:41:31 pm »
back ohh probably 20yrs ago, i was driving down a freeway and noticed a car with the hood up and i decided to stop and see if they needed any help and they said that they called a cab to come get them and that he was fed up with the car always breaking down and i offered to look at it, and he said ok and ill tell you what here is the title for it its all yours if you want it, ( he was going to go to a car dealer and get rid of it.) and i said ok so about this time the cab shows up and off he goes and i look at it and i see what it is so i run to the parts house and get a new cap and rotor for it go back and put it in and i had friend with me and off we go 2 days later i sold it for a very nice profit.  :-+
 

Offline CatalinaWOW

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Re: What was your easiest repair ever?
« Reply #88 on: September 23, 2016, 06:25:47 pm »
Adding to a theme mentioned several times above, I was on call to maintain a test station worth over a million dollars (in the dollars of four decades ago).  Arrived in response to a trouble call and it took less than a minute to observe that the equipment function far better with the power cable plugged in.  Someone had kicked it out without noticing.
 

Offline BurningTantalum

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Re: What was your easiest repair ever?
« Reply #89 on: September 24, 2016, 05:18:36 am »
I once had to make a service visit to look at a non-functioning machine guard system. I flew business from the UK to Hong Kong, then had a three day wait for a visa for China. I then sat all day in Kai Tak due to a weather delay, and got very drunk with my colleague who came along in case the issue was mechanical. We flew down to somewhere near Hainan Island and went to the factory the next day. While my colleague was organising a jar of tea leaves I opened the panel, saw that one of the relays was a different colour and was in fact an AC type. I pulled it out and swapped it for the correct DC type from an unused circuit.
All was then well. We had to wait a week for a return flight, then two days in 5 star Hong Kong and a business return to the UK.
My colleague always told the story as my fix "took 5 minutes" but in fact it was nearer to 20 seconds. I don't know the cost per second to the customer, but it must have been considerable.
BT
 

Offline BurningTantalum

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Re: What was your easiest repair ever?
« Reply #90 on: September 24, 2016, 05:22:06 am »
Oh, and we had such a row whilst drunk at Kai Tak that he was still trying to throw punches at me as I dragged him to the gate. Neither of us could stand up properly, but CAAC was quite forgiving in those days. They gave us more drinks once airborne !
BT
 

Offline SeanB

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Re: What was your easiest repair ever?
« Reply #91 on: September 24, 2016, 06:41:21 am »
A Keithley 4 quadrant source.  I'd have to find the number. Wrote a  program to exercise the OUTPUT ON relay overnight.  Fixed  the next morning.

Was told a story by an ex colleague of mine, he worked at ICL in Cheshire back in the day when we Brits made computers.

One of his colleagues developed a test rig for the pneumatic valves used in tape units for the (I *think*) ICL 2900 mainframes, said test rig would exercise the valves and help eliminate failures.

Sadly for him, the rig didn't take into account the lifespan of the valves and after a weekend long run he came into the workshop to find several thousand pounds sterling of wrecked pneumatic valves.

Reminds me of fixing ATE relay boards. Bad board, so swap with a spare ( lots of fixed boards) then take the board, look which relay was faulty ( mostly high contact resistance on the mercury wetted relays) and remove the relay, tap it on the bench to get the mercury drops back to the one end, and tap again to move them back to the contact area, then test it again. most of the time it would pass resistance testing and be soldered back in the board. Nice that the ATE test program ( which took around 3 hours to run) would tell you exactly which contact and which relay was faulty, along with being able to diagnose cable faults in the test looms as well, using the special loopback test configuration block and the loopback testing lead set.
 

Offline setq

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Re: What was your easiest repair ever?
« Reply #92 on: September 24, 2016, 10:45:38 am »
Not one thing specifically but literally everything I buy as dead as untested so far just needs cleaning and works properly!
 

Offline Messtechniker

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Re: What was your easiest repair ever?
« Reply #93 on: September 24, 2016, 01:24:07 pm »
PC dead as a Dodo. Should have gone to waste.
As so often: one bulging electrolytic in the PSU trying to blow its head.
Replaced with the same type salvaged from a very old motherboard.
Works. However, would not use it for anything critical.
C had 17 uF instead of 1000 uF.


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Offline R005T3r

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Re: What was your easiest repair ever?
« Reply #94 on: September 24, 2016, 01:36:33 pm »
My easiest repair ever done was:
Unplug the pc from all the calbes
slide off
connect the Hard drive sata cable
slide on
connect

50 bucks earned in 1 minute
 

Offline HackedFridgeMagnet

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Re: What was your easiest repair ever?
« Reply #95 on: September 24, 2016, 02:53:33 pm »
Went around to fix this ladys oven, she was keen to do some cooking so she said she would kiss me if I could fix it.  :)
This was in front of her mother and father too, who were a bit embarrassed about this offer, like myself.

Anyway I tried my damnedest to fix it but couldn't figure it out. So I said I would take it away and try to fix it at home.  :(

When I got it home I somehow got it working, I cant even remember how, possibly a bad connection on what should have been the neutral, anyway it didn't need parts.
So I rang her up, by this time it was about 3 hours later and she said she had already bought another oven!

So I missed the kiss but got the old oven.
It's a good oven, 2 in 1, Still going strong.
 

Offline retrolefty

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Re: What was your easiest repair ever?
« Reply #96 on: September 24, 2016, 03:38:26 pm »
In the U.S. Air force it was known that many airmen would write out their maintenance report:
"No problem found, suspect intermittent SBH, short between the headsets"  :-DD
 
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Offline SeanB

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Re: What was your easiest repair ever?
« Reply #97 on: September 24, 2016, 05:47:57 pm »
I used to work on avionics, and got a bomb aiming computer in with the following terse description of the issue " First bomb fell on target".

Phoned the pilot in question, and asked for a little more info. Thanked him, then checked where the plane was, and. as it was in for a scheduled maintenance cycle, phoned the shop and asked the relevant person to check a certain part. Then tested the unit, and sent it back out with absolutely nothing wrong with it. Didn't get feedback ( regular thing) but guessed that another box went off to another service unit on the scheduled mail delivery.
 

Offline JacquesBBB

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Re: What was your easiest repair ever?
« Reply #98 on: September 24, 2016, 06:05:11 pm »
I got once a ISO-TECH IPS2303 (same as Instek GPS2303) Power supply in the dumpster of a  physics lab.
quite new  2 x 30V 3A lab PSU.

I was ready to make a  serious work on it, and  start to open it, when I realised that the fuse was blown. I could have even avoided to open it as the fuse is on the plug and accessible from outside. I replaced the fuse and its working fine since.

What strikes me is that this comes from a physics lab where they are supposed to know quite a lot on electronics.
 

Online Berni

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Re: What was your easiest repair ever?
« Reply #99 on: September 24, 2016, 06:07:14 pm »
I bought a HP 8082A Pulse generator (Up to 250MHz and 1ns rise time) off ebay where the seller claimed it does not power on. But it was in nice condition and got it for like 50 bucks.

When it comes in the mail i see the fuse is missing so i put one in. Then i tried powering it on and there was no power light however i could hear a transformer hum in it. So i check the output BNC and we got a signal, everything worked. So then i opened it up and to figure out why the power LED was not turning on i used a multimeter to check if there is voltage coming to it. But once i touched a spring loaded contact behind it it lit up so it just had a bad connection and i found out that its a incandescent light bulb not a LED.(Yeah its a very old instrument)

So yeah the fix was basically putting a fuse in it
 


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