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Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Moderator – North American QRO Group at Groups.IO. email: <mailto:[email protected]> [email protected] From: Bruce Forsberg <[email protected]> Sent: Saturday, July 24, 2021 11:10 PM To: [email protected] Cc: [email protected] Subject: Re: [Elecraft] KPA500 270V Failure OK, I see what you're saying now. I might have 2 problems. 1 or more diodes in the PS board and the TR switching diodes. I will make the check you stated. Thanks for the tip. Bruce, WB6IZG On Sat, Jul 24, 2021 at 9:03 PM Dr. William J. Schmidt <[email protected] <mailto:[email protected]> > wrote: Well my experience is that the supply doesn’t just die for no reason… Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Moderator – North American QRO Group at Groups.IO. email: <mailto:[email protected]> [email protected] From: Bruce Forsberg <[email protected] <mailto:[email protected]> > Sent: Sunday, July 25, 2021 5:55 AM To: [email protected] <mailto:[email protected]> Cc: [email protected] <mailto:[email protected]> Subject: Re: [Elecraft] KPA500 270V Failure Thanks for the reply but in my case the problem is the voltage multiplier circuit on the power supply PCB. I just disconnected the HV (~70V) and 270V lines so they did not go anywhere and the 270V line still only measures 85V. Thanks Bruce, WB6IZG On Sat, Jul 24, 2021 at 8:36 PM Dr. William J. Schmidt <[email protected] <mailto:[email protected]> > wrote: Here it is. From Elecraft technical support: Nominally: TP2= RX 13.1 TX 0.8 TP4= RX 3.9 TX 13 From Rene Morris at Elecraft (great guy!). Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Moderator – North American QRO Group at Groups.IO. email: [email protected] <mailto:[email protected]> -----Original Message----- From: Dr. William J. Schmidt <[email protected] <mailto:[email protected]> > Sent: Saturday, July 24, 2021 10:35 PM To: 'Bruce Forsberg' <[email protected] <mailto:[email protected]> >; '[email protected] <mailto:[email protected]> ' <[email protected] <mailto:[email protected]> > Subject: RE: [Elecraft] KPA500 270V Failure This happens a lot... search the forum for past msgs. It's not the HV power supply that is the problem. That power supply powers the PIN diodes for TR and RX... and it is more likely that the PIN diodes shot craps and shorted the power supply. There are two voltage Test Points "TP" on the board under with the diodes and you need to check the voltages on those test points. That will tell you everything you need to know. Will post the voltages when I find them. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Moderator – North American QRO Group at Groups.IO. email: [email protected] <mailto:[email protected]> <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> Virus-free. <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> www.avg.com -- This email has been checked for viruses by AVG. https://www.avg.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
