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Old 30th Dec 2017, 5:20 pm   #1
Mylkinut
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Default Bush TR82B problems

Hi all - brand new to the forum as well as vintage radios (please forgive my lack of knowledge!).

I recently inherited a Bush TR82B which I'm quite keen to see if I can get going and learn something new in the process. I've got some soldering skills (mostly from modding/repairing guitars). If it's not worth the effort it's no great loss - it looks quite pretty on the shelf anyway!

The current situation is this:
  • It has a new battery in it
  • Switches on, but only static comes through the speaker
  • Volume and tone pots both seem to be functioning and reasonably crackle-free after some contact cleaner
  • After switching between Med and Long repeatedly (to see how the mechanism worked, largely out of curiosity) it started picking up a station, albeit it with a fair amount of static. I couldn't move away from this station using the tuning dial - it was stuck on that station.
  • That lasted about 10 minutes - in that 10 minutes it dropped out a couple of times, but switching to Long and back again kicked it back in.
  • Now I can only very faintly hear voices and music, and it's almost all static.

The serial number is 345/06551 - I believe this is an earlier one without the AF117 transistors but I could be wrong.

Where should I start looking to diagnose its problems? Any help would be brilliant. I've attached some pictures if it makes things easier.

Thanks!
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Old 30th Dec 2017, 5:28 pm   #2
Station X
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Default Re: Bush TR82B problems

Hello and welcome to the forums.

As far as I know these sets used OC series transistors.

I'd start by applying Servisol to all the pots and switches.

I'm not normally one to advocate wholesale component replacements, but those red/yellow/black Plessey electrolytic capacitors are unreliable.

The correct approach is to measure voltages and compare them with the service sheet.

http://www.service-data.com/product.php/655/1065/m10655
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Old 30th Dec 2017, 5:39 pm   #3
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Default Re: Bush TR82B problems

It's probably the wavechange switch contacts which tend to oxidise.

It's clear from the photos that OC44/5 transistors are fitted which are generally reliable.
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Old 30th Dec 2017, 8:00 pm   #4
60 oldjohn
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Default Re: Bush TR82B problems

I had one with similar fault, once the wave change switch has been cleaned, try a bit of GENTLE heat on the three black transistors OC44 / 45. in my set warming between finger and thumb would be enough for the set to burst into life.


John.
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Old 31st Dec 2017, 11:27 am   #5
Scottart
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Default Re: Bush TR82B problems

I've recently restored one of these radios.
The wave change switch was horribly dirty/oxidised, but after careful cleaning ( Deoxit / IPA etc ), it now works fine.
I also replaced the Plessey red/yellow/black electrolytics - not known for their reliability.
Stephen
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Old 31st Dec 2017, 2:13 pm   #6
Mylkinut
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Default Re: Bush TR82B problems

Brilliant - thanks everyone for their responses! I've managed to get hold of some Servisol from my in-laws so I'll get the wave change switch cleaned up once I'm back home. Will also give warming the transistors a go.

Thanks again everyone - will update with any progress as I go!
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Old 31st Dec 2017, 6:51 pm   #7
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Default Re: Bush TR82B problems

Quote:
Originally Posted by 60 oldjohn View Post
I had one with similar fault, once the wave change switch has been cleaned, try a bit of GENTLE heat on the three black transistors OC44 / 45. in my set warming between finger and thumb would be enough for the set to burst into life.
Slightly off topic, but curious to know how warming Ge transistors would restore operation...
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Old 31st Dec 2017, 7:19 pm   #8
60 oldjohn
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Default Re: Bush TR82B problems

Hi Keith, not sure but it worked for me, and kept working until switch off. Upon turning on again it needed warmth again, and ultimately another transistor.


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Old 31st Dec 2017, 10:13 pm   #9
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Default Re: Bush TR82B problems

I have not known these OC transistors to respond like that. I wonder if that was the real cause of it starting to work or if during the time you were "warming" the transistor a capacitor reformed enough to get the set going.

Mike
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