[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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