Strangest electronics repairs - Page 4 - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 26th December 2011, 01:16 AM   #31
minsik is offline minsik  Australia
diyAudio Member
 
Join Date: Mar 2011
Location: Sydney NSW
Default In the theme- strangest electronic repairs. some more.

In my previous working life at my consumer electronic repair workshop.

1) reception came to get me, did i think i could repair this. What is this. A large metal object about the size of a mans arm, Hmmm. what does it do. Hmmm. tame receptionist described (as she had recieved the information form the customer. " Well its like this, this is inserted in the Bull's rectum and its turned on, then the agricutlural assistant collect the semen then is deposited out of his .... "
At least it was a only a connecting wire repair. when it came to testing time there was an absence of technicians.....

2) Reception told me, thing looks like an oscilloscope needs repair. Ok what does it do? Its a sheep pregnancy tester. Ok. Repaired power supply. tested on different input signals ok. My wife was pregnant at the time but would not allow any after repair testing!

3) Pulrple smoke fromt he television, Dont be stupid my receptionist. It might be brown, black or grey. No way is purple smoke coming out of a television! I will show you. Plug in TV, turn on. Some sort of crackle noise but no sound or picture. In 30 seconds BRIGHT PURPLE smoke rising from the back of the tv in a spiral like a snake. Ok dont breath the fumes and turn it off quick smart.. Traced to FBT must have contained fibreglass resin and it was burning from arcing windings.

So now i say, customer is allways right until proven otherwise.

Just a few stories from 30+ years servicing as tv,video, audio, and communications serviceman in small country town in South Australia.

minsik.
  Reply With Quote
Old 28th December 2011, 01:13 PM   #32
diyAudio Member
 
thaumaturge's Avatar
 
Join Date: Aug 2011
Location: Utah
Never saw bright purple smoke, I must admit. Think that would have weirded me out as well. But I did make WHITE PLASMA once by forgetting to switch on the cooling pump on an RF dummy load and running a 22KW VHF Analog TV transmitter into what was then basically a 200Watt ceramic 50 ohm resistor. Quite pretty. Ate a 5mm slot about 30mm long in the aluminum housing before the SWR protect cut in and shut things down. I was heading that way anyway after seeing the plasma. A replacement load head was about $2000 at the time... but the previous engineer had done the same and the boss said one per engineer. Only reason load wasn't interlocked was because it was used on three different transmitters. I rebuilt both the one that I burned up and the one the previous engineer had. Both good for 50KW.
Doc
__________________
Ne timeas a facie mulierum ea ignorare
  Reply With Quote
Old 29th December 2011, 07:19 AM   #33
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
This was my personal TV, a Sony KX2501 / VTX1000R. July 4 1986 around 10 PM heard a soft whistling followed by a POP and some white smoke out the top OF THE TV when a 'lytic capacitor failed. Since there were fireworks going on outdoors I didn't immediately make the connection.

G
  Reply With Quote
Old 3rd January 2012, 01:15 AM   #34
diyAudio Member
 
deadpool's Avatar
 
Join Date: Jul 2009
Location: Melbourne
Im a Sony service engineer (well thats what they call us these days)

I remember a very strange fault with Sony VCR (H mechanism for those who know), The unit has come a simple repair just a faulty capstan motor (not starting up), but due to some miscommunicastion the client had thought the unit was repaired and decided to come into the store on a Sat morning to collect, fair enough but I hadn't finished the repair yet. So my manager asked me to quickly finish the mechanism repair urgently. Confidently I finished off the job even put the lid back on as I had done at 50 of these mechanisms before. So just before I sent the unit out I threw a cassette in and the unit ejected it straight away after lacing it up around the heads, very strange! Tried again, same thing just ejected the cassette, tried again, same thing!...no error codes just ejecting all the time....suspect the cassette, tried another, no still ejecting, decided to quickly remove mechanism and check timing, all good, gears all fine, mode switch correct, reinserted mechanism into unit...still ejecting!..mmm very strange...My manager came in and said whats up customer is waiting etc...I showed him, he looked as mystified as me...so pulled another complete unit out which i had and put its mechanism in my repair...still ejecting!...damn it...Now I had this other unit on another bench a few meters to the left of me...so i decided to put my rebuilt mechanism in it...it worked fine...mmm...okay quickly do a complete board swap...no still ejecting on my bench..but both units all working okay on the other bench..WTF...Turn around and look over my shoulder...We have a rack of completed repairs...there I see it...#@$@#$ me someone has put a competed VCR repair on the rack but with its remote tapped to the top of the unit...the unit has moved the remote has jammed and is transmitting the eject function...case solved finally...not happy
__________________
'Beauty is the promise of happiness'
  Reply With Quote
Old 3rd January 2012, 01:36 AM   #35
diyAudio Member
 
nigelwright7557's Avatar
 
Join Date: Apr 2008
Location: Carlisle, England
I had a power amp that kept blowing up while I was working on a mixer plugged into it.
It kept on smoking the class d output filter capacitor. Couldnt work out why.

Eventually it dawned on me that right above the mixer I had a mains lamp that was low energy and its oscillator was getting into the mixer and putting the very high frequency into the power amp in a big way.
  Reply With Quote
Old 3rd January 2012, 11:10 PM   #36
diyAudio Member
 
thaumaturge's Avatar
 
Join Date: Aug 2011
Location: Utah
In my earlier days working on SMPS on computer monitors I didn't understand that they would shut down or throttle back on an over current condition. I had one stuborn one that I modified until it RAN.... immediately smoking the three bad parts that were keeping it shut down.
Doc
__________________
Ne timeas a facie mulierum ea ignorare
  Reply With Quote
Old 4th January 2012, 02:54 AM   #37
benc is offline benc  United Kingdom
diyAudio Member
 
Join Date: Apr 2010
Location: UK
back in the early '90's I was working for one of the more interesting Govt. departments.

I'd spent a solid couple of weeks prototyping this design I had come up with, loads of 74 series (about 30 IC's in total), some 4000 series a few opamps etc.. Powered it up - nothing. Spent two days checking every single bit of wirewrap at least three times. After the two days I was almost crying with frustration - nothing - no signals at all - PSU's all fine, but not a sausage. Then a senior chap suggested I go and have a cup of tea and do something else for a change. When I returned (refreshed) from the canteen I immediately spotted the problem - I hadn't put any IC's in the wirewrap holders....

Same dept. different month. Just fixing a CRT monitor for a nice female (and my senior) colleague - dry joint on a small electrolytic capacitor, decided to impress her by changing the electrolytic rather than just resoldering the leg. Replace the part, whilst trimming the leads on the capacitor, one of the trimmed leads is launched 6 feet across mine and my colleagues bench (over-enthusiastic chomp with the Lindstroms..) and into the back of another CRT monitor where it proceeds to go **bang** and dark.

Same dept. Dropped a brand new loaned 40K network analyser in-front of the rep (didn't realize it was so-heavy), very professional chap - his smile barely flickered (we did spend mega-bucks with them).
  Reply With Quote
Old 4th January 2012, 03:23 AM   #38
diyAudio Member
 
wrenchone's Avatar
 
Join Date: Feb 2004
Location: Silicon Valley
That senior chap had the right idea. Sometimes you just need to lay aside whatever project is frustrating you for a while and work on something else. This is a luxury usually not available except to us DIY types, as bosses want things done to schedule (or before).
  Reply With Quote
Old 4th January 2012, 03:27 AM   #39
diyAudio Member
 
Join Date: Nov 2011
Years ago I used to work on mainframe computers. At one customer site, they were experiencing magnetic tape drive problems but only during a certain time interval in the afternoon. On attending the site in the particular time period I observed that the windows in the computer room faced on to a heavily trafficked road and sunlight was reflecting off car windscreens directly into the room. This was playing havoc with the optical sensors in the tape drives that maintained the tape height in the vacuum buffer columns. Curtains solved the problem.
At another site in a ten story building, commisioning of the new system was delayed because of a disk drive read error problem. Diagnostic programs were of no help but a physical inspection revealed that the head drive carriage would oscillate rapidly back and forth for a second or so about every twenty seconds. The penny eventually dropped.
They had a direct line of site to the cities busiest airport and, every time the radar swept across them, the modulation caused the servo to oscillate. Shielding the wall on that side fixed the problem.
  Reply With Quote
Old 4th January 2012, 03:29 AM   #40
diyAudio Member
 
thaumaturge's Avatar
 
Join Date: Aug 2011
Location: Utah
Quote:
Originally Posted by benc View Post
Same dept. Dropped a brand new loaned 40K network analyser in-front of the rep (didn't realize it was so-heavy), very professional chap - his smile barely flickered (we did spend mega-bucks with them).
One day at a Litton div. in Silicon Valley I found our lab expediter trying to move about $680,000 worth of HP8566 spectrum analyzers (10ea) on two overloaded carts. I suggested it would be okay to make several trips.

Inside story floating around Silcon valley about when the military was making selection of 100Mhz scopes. They had all the candidates on a conveyor belt and sumeone switched it on and dumped the lot on a cement floor. They picked the two that lived (HP1740A, Tek 465B).

Doc
__________________
Ne timeas a facie mulierum ea ignorare
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
ESL electronics 101 for the electronics challenged markusA Planars & Exotics 12 29th April 2011 05:19 PM
White Series 4000 EQ The strangest PSU design EVER. GLORY_MORRIS Parts 15 23rd October 2008 12:53 AM
Whats the strangest enclosure you found to work? Scioneer Full Range 0 20th September 2006 03:54 AM
The strangest thing Nielsio Multi-Way 13 10th April 2006 08:05 PM
Your Nicest, Rarest or Strangest tube Netlist Everything Else 28 17th May 2003 03:20 PM


New To Site? Need Help?

All times are GMT. The time now is 06:53 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2