Richard -
The fact that it didn't tune indicates that perhaps the antenna was
either not connected (relay?) or wrong band? or bad coax, or ...
Possibly arcing in the relay contacts or coil.
What is the BIAS current? It should be 100 mA, if it's now 65 mA or so
you may have lost a final tube.
Really not much to flame in the PA cage. You could get corona on
variable cap plates, again due to mismatch, but that is typically an
ozone smell. A parasitic could have fried one of the parasitic
suppressors on the PA plate caps. Are all three PA tubes from the same
manufacturer?
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Richard Palmer wrote:
My TR-4 did not want to tune... it caught on fire that looked like it
was at the PA section probably around the relay. All I could really do
was grab switches and plugs faster than anything I've done in the last
twenty years.
The smoke was not the conventional electric smell. It was very acid
and burning. I sorta took in a nose full doing the above and felt
high, in a bad way. I just got around to looking at it and can not
find any burnt or distorted part. There is absolutely no sign of soot
or heat anywhere. Seeing this I tried to tune her up again. I was
getting a very solid 4.5 for the plate current. Now it's only 3. Is it
possible (likely) that I "smoked" one of my PA tubes?
Thanks in advance,
Richard Palmer
KB8NXO
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