[Elecraft] FW: KPA500 faults

[Naumann, Robert, W5OV]

What line voltage are you running it on?  If you're not on 240v, switching to 240v would be the easiest and most effective improvement.

Doing so yields a 4:1 improvement in line voltage regulation / reduction in voltage drop.  Double the voltage, at half the current draw.

73,

Bob W5OV

-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of Dr. William J. Schmidt
Sent: Thursday, March 3, 2022 00:39
To: elecraft at mailman.qth.net
Subject: [Elecraft] KPA500 faults

I have a KPA500 that faults on low (60 VDC) voltage.  After measuring the power supply voltage at the PA module is perfectly fine.  The voltage read by the processor on the front panel via pin 10 of P1 is lower than it should be and hence the fault condition.  I suspect there is a voltage divider on the LPF board that drops the 60 VDC to something that the processor can read and digitize (in the 0 to 3-5 volt range).  The set of schematics I have do not show the voltage divider anywhere. does anyone have this part of the schematics for the KPA500 so that I can adequately troubleshoot this amp and
get it on the air for the contest this weekend?   Multiple notes to Elecraft
have gone unanswered.

 

 

Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

 

 

email:   <mailto:bill at wjschmidt.com> bill at wjschmidt.com

 

 

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