HELP! KPA-500 HV is 10 Volts

[Tom Zeltwanger]

Just got a repaired KPA-500 PA/LPF module from Elecraft and installed it
in my KPA-500 Amp. I carefully (I thought) reassembled everything. When
I powered-up the unit and tapped "HV" I get numbers between 9 and 11
volts (expecting ~ 65 or 70 Volts). I know this is not right. I
double-checked the 270V line to the PA module and the top cover
interlock. Surely I am doing something stupid.

Any ideas?

73,

Tom, KG3V


--
Get on the Air and make some noise
Ham Blog at WWW.KG3V.COM


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[ANDY DURBIN]

"When I powered-up the unit and tapped "HV" I get numbers between 9 and 11
volts (expecting ~ 65 or 70 Volts)."

I'd suggest measuring the actual HV rail at the PA input spade terminal.  That will tell you if you have a real low voltage problem or a voltage sensing problem.  The interlock switch will need to be defeated which is not difficult but I leave that to your ingenuity.

If the voltage really is low then (switch off) disconnect the 60 V bus from the PA module (switch on) and measure again.  My HV supply is 80 V unloaded.

The interlock switch is there to stop you doing this so don't defeat it without considering the risks and taking appropriate precautions.  

73,
Andy, k3wyc



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