[Boatanchors] Amp Supply LK500-ZC Amplifier Question

[Mark K3MSB]

Gentlemen

I'm am troubleshooting an Amp Supply LK500-ZC linear amplifier for a club
member.

I've diagnosed the problem to the Jennings vacuum relay at the amplifier
output.   It is a Kilovac FSCM 18741 8828.

I am measuring about 12 volts at the one end of the coil, and the other end
goes to about zero when I close the external TR relay.   This, combined
with a correctly working transmit indicator is telling me the associated
transistor is working OK.

The relay, which had been working OK in the amp for decades,  is a 26.5 VDC
335 ohm coil.

The coil is fed from 20 VAC through a half-wave rectifier, so the measured
reading of 12 VDC at the input end  of the coil is in the ball park.

I'd like to know why it's a 26.5 VDC relay when the firing voltage is only
around 12 volts.  This relay is fed from the QSK board.

Thanks & 73

Mark K3MSB