[Collins] Back trouble shooting the KWS-1 Need Help

[Dave Meitzen]

Symptom: When I adjust the bias to set the PA idle current at 100Ma it
slowly declines to zero.

Bias circuit is good. Swapped the finals so next checked the screen circuit.
This is what I see.

The screen voltage slowly declines (screen current as well) to ~200vdc. I
scoped the screen voltage and do not see any ripple. This tells me the
screen supply has good caps. The voltage does not decline.

If there was a bad bypass I would think it would blow the fuse?? The screen
fuse is 0.25 amp.

Before I disassemble the amp I thought I would ask.

Anyone out there seen this before?

Thanks
Dave