Thanks to the 2 people who replied. Thanks to Keith VE7KW who had R16 (100 Ohm) SMD resistor fail on his PS board in his KPA500. I had the same problem here. R16 tested open. It does not appear to be cracked or burnt, just a failure. R16 appears to be a resistor that feeds the voltage multiplier circuit for the 270V line.
Bottom line is my KPA500 is back in service. Bruce, WB6IZG On Sun, Jul 25, 2021 at 2:30 AM Bruce Forsberg <bruce.forsb...@gmail.com> wrote: > 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 After finding some old outdated schematics on the 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:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
