[AMPS] AL-80b PROBLEM - ANY IDEAS?

[Floyd Sense]

Just developed a problem in my AL-80B, and not sure what's going on.  When
operating SSB or CW, all is well and has been since I got the amp last year.
I'm getting back on RTTY and was running some tests with the new transceiver
when I noticed this problem.

I key the TS-950SDX in FSK mode with about 40 watts output, driving the
AL-80B to about 400 watts out on 14.080 into a dummy load.  If I unkey the
transceiver within a few seconds, everything returns to normal in receive
mode.  However, if I leave carrier on for 15 seconds or so and then return
to receive, I hear the relay drop in the linear, but I still have 100ma. of
plate current and a resulting orange glow on the plate.  Turning the XMT
switch on the AL-80B to STBY makes no difference.  I have to turn off the
linear in order to get things back to normal.   Perhaps a failure in the
AL-80B bias circuit?  ALC voltage is set correctly, and grid and plate
current are normal with key down just before the failure.

K8AC
Floyd Sense - Angier, NC


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