James I had the 270 V Err message on my KPA500 as well, S/N 3406. It turned out to be R16 on the PS board had opened (S/B 100 ohms). This resistor feeds the voltage multiplier circuit to get to 270V. Don't know if this is your problem or not but does not hurt to check. It is an SMD resistor and I think is accessible from the top.
Bruce, WB6IZG On Sun, Jul 17, 2022 at 2:51 PM James Bennett via Elecraft < [email protected]> wrote: > Hi - I’ve had my KPA500 serial number 3645 for several years and until > today have had zero problems with it. Previously it was driven by a K3; > currently (until today!) a K4D. Last time I used it, it worked great. Today > I powered it on after having it off for several days and when I went to > Operate mode, I got the dreaded 270V ERR display. When I display HV it > shows “1”. Everything else seems to be OK - band changing works fine, > metering of the power and frequency are OK - just can’t go to Operate mode. > The top cover is on just as tight as it has been for years. Fuses are all > OK. > > Looked through the archives and did see a few hits, but most were related > to loose top cover or incorrect voltage settings. > > I’ve fired off an email to Elecraft support earlier today but thought I’d > run it by the owner community too. > > Suggestions? > > Jim Bennett / K7TXA > Eagle, ID > > > > ______________________________________________________________ > 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] ______________________________________________________________ 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]

