[Amps] WD7S lack of HV circuit ?

jim.thom jim.thom@telus.net jim.thom at telus.net
Fri May 31 09:58:45 EDT 2024


WD7S, on one of his boards he sold, was made to shut things down in the
event of loss of B+.
If I remember correctly, it resembled a mess of series resistors, like you
would use to meter HV, (without the meter), and an extra smaller value
resistor, in series at the cold end.  The V drop across the small value
resistor was like 5-7 vdc.... and was applied to the rest of the circuit.

When the B+ dropped below a given threshold, the circuit tripped, and
kicked the amp offline...like opening off the keyline etc.  I think it used
a spt, or dpdy mech relay..that was always operated, with B+  turned on.  I
think the coil was opened off when the circuit tripped.

I can't find the original schematic for this board anywhere.
Does anybody have any info on it ?

Jim  VE7RF


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