UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Hints, Tips and Solutions (Do NOT post requests for help here)

Notices

Hints, Tips and Solutions (Do NOT post requests for help here) If you have any useful general hints and tips for vintage technology repair and restoration, please share them here. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

Closed Thread
 
Thread Tools
Old 7th Aug 2005, 11:46 pm   #1
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,550
Default Bush TR82C

I thought I'd share a slightly unusual fault with you all....well I've never had it before anyway. This set was one of two more sets I have been repairing for Howard who frequents this forum. This version was the older type with the OC series transistors. It was, as he had described, completely dead....well except for the usual hiss from the speaker. There was a nice healthy buzz from the base of the OC71 but nothing further back and I mean nothing. No crackles or noise of any kind when touching the bases of the OC45's. Usually some sort of crackle can be heard...Zilch!! Zero!! Voltages around the transistors were about right and when I put my digital meter, set to frequency on the collector of the oscillator, I could see it changing as I tuned the variable capacitor, both IF amps also seemed to be working with the frequency showing near to 470Khz. The fault pointed to the last IF transformer. A quick 'cheat' consisted of connecting a diode from the collector of the last IF amp to the volume control. This produced distorted signals but an otherwise lively set.

I removed the IF transformer and then the can so that I could get to the detector diode inside. A quick meter check showed that this was completely open circuit. I carefully fitted an OA91 in it's place and then refitted the can and then the IF transformer. Switching on produced normal operation and a very sensitive set that required no further work. These really are good sets to work on and put many modern sets to shame.


Rich.
__________________
There are lots of brilliant keyboard players and then there is Rick Wakeman.....
Sideband is offline  
Old 8th Aug 2005, 12:31 am   #2
Darren-UK
Retired Dormant Member
 
Join Date: Apr 2003
Location: Blackpool, Lancashire, UK.
Posts: 4,061
Default Re: Bush TR82C

Well done Rich A somewhat similar fault is not unknown on the Roberts R200/R300 and it's not always that obvious to find. By the way, what's a TR82A ?

Last edited by Station X; 8th Aug 2005 at 1:17 pm.
Darren-UK is offline  
Old 8th Aug 2005, 12:20 pm   #3
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,550
Default Re: Bush TR82C

Quote:
Originally Posted by darren-uk
By the way, what's a TR82A ?

OOps!!! Should be TR82C . It was late when I posted that! Perhaps one of the moderators could correct the heading?


Rich.
__________________
There are lots of brilliant keyboard players and then there is Rick Wakeman.....

Last edited by Station X; 8th Aug 2005 at 1:18 pm.
Sideband is offline  
Old 8th Aug 2005, 1:19 pm   #4
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,193
Default Re: Bush TR82C

Quote:
Perhaps one of the moderators could correct the heading?
OK. Just this once.

Graham.
Station X is online now  
Old 8th Aug 2005, 7:52 pm   #5
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
Default Re: Bush TR82C

Hello Richard,
I laughed when I read your fault with the Bush TR82C. I had that one about 30 years ago with a TR82C but mine produced VERY low volume but numerous stations. That was my clue. I had a FERGUSON 606T television brought to me quite recently by a fellow collector with no sound. He had spent hours of frustration with it. I whipped the can off the final sound i.f and slodered in another OA91 and in three minutes had roaring sound...It reduced him to tears poor lad....Well done! Regards JOHN.
Heatercathodeshort is offline  
Old 9th Aug 2005, 3:57 pm   #6
howard
Nonode
 
howard's Avatar
 
Join Date: May 2005
Location: Godalming, Surrey, UK.
Posts: 2,593
Default Re: Bush TR82C

Hello all,

Richard made an excellent job of my TR82C and TR82D chassis. The TR82C has life at long last and sounds as good as new, and the TR82D with two new AF117s now fitted sounds so much better, the edginess in the sound quality is all but gone. Many thanks Richard for your help, you're definitely gifted !

Regards........Howard
howard is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 10:31 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.