[Collins] 30S-1 problem..

[Dr. Gerald N. Johnson, electrical engineer]

Perhaps the socket or the wiring is getting less than 6.3 volts to the
6AL5. There's nothing OUTSIDE the tube that could make one heater dimmer
than the other, besides low voltage (heaters probably in parallel inside
the tube) and some difference in heating.

Dust on the high voltage insulators, like the RF choke, the blocking
capacitors, the tube, can cause little flash overs. Might lead to
overloads to trip the power supply off. A bad PA tube can draw a lot of
current. Lack of PA bias can cause excess plate current to trip the
overloads.

73, Jerry, K0CQ, Technical Advisor to the CRA
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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
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