Sounds like the amp is plugged into an outlet that is potentially overloaded or underrated.
Changing the tap won't solve the problem and may damage the amp. 73, Cliff K3LL -----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of Matt Murphy Sent: Friday, November 20, 2015 7:46 AM To: Elecraft Reflector Subject: [Elecraft] KPA 500 voltage drop on key down I just set up my KPA 500 and the HV on standby is 72.5 volts. On key down, however, it drops to 48 volts and the lights in the shack noticeably flicker a bit. Would changing a the tap on the transformer potentially help things? Or is the real issue the voltage drop between the pole and the wall socket? Suggestions/ideas would be much appreciated, as well as tips for debugging any issues with the household wiring. Per the KPA 500 manual, the amp may fault if the voltage under load gets below 60VDC, so running in it with reduced drive may be necessary. While doing that wouldn't be the end of the world, I'd like to address the root cause if possible. 73, Matt NQ6N ______________________________________________________________ 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]

