[NJARC] Advice Needed:
Al Klase
al at ar88.net
Tue Jan 1 12:08:31 EST 2008
Hi Joe,
The transformers in a lot of these old sets run warm/hot. The solution
to that, in the original design, was more iron and more copper, but they
cost money. The question is how hot does it run? Can you keep your
hand on it for a while? If you can that's less than about 125 F, and
should be OK. The "tar shower" was probably the result of overload at
some point as components were failing. If the thing still get hot
enough to melt tar, I would play the set for any length of time, and
start looking for a replacement.
You also might want to check that the 41's have correct grid bias, and
aren't drawing excessive current. The output tubes are the primary
power consumers in most radios. The bias is easy to measure, as the
cathodes are grounded in this set. 41 is equivalent to a 6K6. The tube
manual shows the bias should be -25.5 for 285 volts on the plates
(push-pull class A1).
Al
JOE CRO wrote:
> ......Has anyone else in our group come across a situation like this? If so, what did you use to repot the transformer? I was thinking of silicone RTV, but due to it's curing properties I don't know if it would be a suitable medium to use. Should I just leave it alone and hope for the best? Again, any advice will be greatly appreciated.
>
> Many thanks in advance for any advice, and a very Happy new year to all. May 2008 bring you more radio that glow in the dark!
>
>
--
Al Klase – N3FRQ
Flemington, NJ
http://www.skywaves.ar88.net/
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