Gents,
Any idea what fault would cause my old and previously faithful Amp Supply Co
LK550 sometimes to register ~400mA of plate current and negative grid
current, even with no PTT and no drive?
First time it happened it took me a while to notice and, judging by the hot
smell, something inside very nearly let out the smoke. After leaving it off
for a few days to cool off while I mulled over what might be wrong (without
any inspiration :-( ), I plucked up courage to switch it back on and it's
working OK now, most of the time, but I've noticed the neg current thing
again, including one time immediately after switched it on, even before the
ALO trip circuit would normally let me transmit. This time it cleared
itself.
[I know I should pop the lid and look for charcoal but first I'm trying to
comprehend what the fault would be. It's part of my 'self training in
amateur radio'!]
73
Gary ZL2iFB
PS Any idea where I might find a new bandswitch for the old amp? I changed
the padder caps recently but it still maxes-out on tune and or plate C on
the low bands, so I strongly suspect the switch is no longer connecting the
padders.
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