My first thought was that this would be easy to set up with a
opto relay across the bottom resistor but on second thoughts, It
might be a bit more challenging because you have the bleed down of
the filter caps to contend with, on the DC side of the HV supply,
so there would be a substantial time delay in the tripping off.
The resistor voltage divider would need to be on the secondary
side of the transformer, before the rectifier and that's where it
gets tricky for a boy with a brain like mine.
Good luck, Alek VK6APK.
On 31/05/2024 10:01 pm, Jim VE7RF
wrote:
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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
