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

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Reply
 
Thread Tools
Old 12th Oct 2019, 10:27 pm   #1
'LIVEWIRE?'
Dekatron
 
'LIVEWIRE?''s Avatar
 
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,078
Question How to decarbonise Paxolin (SRBP) Tagboards, etc?

In a long thread by P.F. Vaughan about modifying the Bush DAC90A, mention was made of Decarbonising paxolin panels such as the tagboard which, in this model, holds the mains dropper and other large resistors, but no mention is made of how to do this. Presumably some dry cleaning agent which neutralises/removes carbon without damaging the SRBP of which the board is made is used, but can anyone enlighten me as to what to use for this job?
'LIVEWIRE?' is online now   Reply With Quote
Old 13th Oct 2019, 9:55 am   #2
boxdoctor
Heptode
 
boxdoctor's Avatar
 
Join Date: Sep 2010
Location: Ripley, Derbyshire, UK.
Posts: 711
Default Re: How to decarbonise Paxolin (SRBP) Tagboards, etc?

If the board is deeply carbonised, then the only remedy is replacement. As the word implies, the material has turned to carbon, which is a good conductor of electricity, and thus is no longer an insulator and therefore inadequate for the job.
If you are sure that the carbonisation is only on the surface, I would try some scouring powder on it, followed by Brasso or similar finer polishing material.
Personally, I would replace the board with some new material, as future failure is quite likely once carbonisation sets in. Tony.
__________________
The job "couldn't be done".
He didn't know that,
So he did it.
boxdoctor is offline   Reply With Quote
Old 13th Oct 2019, 10:06 am   #3
'LIVEWIRE?'
Dekatron
 
'LIVEWIRE?''s Avatar
 
Join Date: Mar 2006
Location: N.W. Oxfordshire(Chipping Norton)
Posts: 7,078
Default Re: How to decarbonise Paxolin (SRBP) Tagboards, etc?

I have recently started to wire up the Dial lamp shunt, HT surge limiter and HT filter resistor of a DAC90a onto a replacement tag-board kindly supplied by a fellow forum member (The original fractured when I overtightened the screws securing the dropper to the board!). The replacement board is in very good condition after I gently rubbed the 'dropper end' with glasspaper, so, hopefully it will be OK. I did think of using a new tag-bard and no doubt one of suitable dimensions could be modified for the purpose, or maybe the dropper could be mounted independently of the board via an additional metal bracket at the top instead. This would remove the main source of charring, although as the original board lasted over 60 years, that more than vindicates the designer's use of this material and mounting method!
'LIVEWIRE?' is online now   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 4:24 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 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.