Hi guys,
I have a spiteful old 30L-1 that is giving me fits, a little background:
I had a filament short out to the B+ and blow a few items in the PS. I
replaced the "fuse" resisters R17 and R18, and also C25 blew up, which was
replaced. Whilst I had her tore apart, I replaced the Diode board with the
K1ROD board. I also installed a new set on JAN 811A's. The Power Supply
caps had been replaced a few years ago, so I left them alone.
Upon re-assembly all seemed OK on 20 Meters, but it tuned up differently
than before, in fact it seemed like the loading capacitor had to much
capacitance. 10 Meters would not tune up and a parasitic suppressor
started smoking while I was trying to tune it up. I shut her back down and
tore it back apart. Checking the tuning cap I found a little debris between
two of the plates, but lost the debris before I got a chance to see what is
was. It may have been carbon, but I just did not see it very well. I
desoldered the loading cap and all four sections had the proper capacitance
values. I re-assembled it and it acted the same.
I cannot load the amp on any other bands, and on 10 Meters a parasitic
suppressor gets very hot, because the circuit is not resonant, I believe,
but it is the one that is connected to the tube that shorted out.
I have visually inspected the coils and they "look" OK, but I no way to
check the actual inductance. I also inspected the band switch thinking
maybe it failed and but there was continuity on each pad for the tapped
coil, so it is OK.
It would seem to me that an inductor has failed somewhere, in the output
tank maybe, but I can't figure it out.
I also desoldered and checked all of the mica caps for the grounded grids
and etc, and they all checked out fine.
I guess at this point I am stuck, and any suggestions would be greatly
appreciated.
Thanks for any help!
73,
Eric
K8CCA
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