SB-201 no plate, high grid

[Michael Waldrop]

The SB-221 572B tubes have -2 VDC applied to the grids in transmit.
This is accomplished by relay RL-1 that grounds, in transmit mode,
the grids and removes all but -2 vdc from the 572B grids.

If RFC2 and/or R15 are open, there will be no operating bias applied
to the 572B grids. Without the operating bias, the tube will conduct
and cause excessive plate current to flow in both tubes.

Check RFC2 and R15 to see if they are open.

73's
Mike
W5RKL

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