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] -----Original Message----- From: [email protected] <[email protected]> On Behalf Of Bruce Forsberg Sent: Sunday, July 25, 2021 4:31 AM To: [email protected] Subject: [Elecraft] KPA500 270V Failure Today when using my KPA500 I switched it into operate mode from standby and received an error message of 270V ERR. This is the first time I have seen this error. I partially disassembled the amplifier and measured the 270V voltage and it is 70V, which is close to what the HV voltage measured on the front panel says. After finding some old outdated schematics on the internet it looks like there is a diode capacitor voltage multiplier circuit that takes the HV voltage of approx 70V and brings it up to 270V. I am assuming I have lost one of the diodes in the chain. Unfortunately Elecraft has used tiny diode packs and even put 2 of the 3 packs between electrolytic capacitors on the board, which I will have to remove. Has anyone else seen this problem with their KPA500? And how did you go about fixing this? Thanks, Bruce, WB6IZG ______________________________________________________________ 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] -- 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]
