Matt, refer to your Owner's manual section, "Power Supply Transformer Tap" starting in page 8 to set the transformer tap.
Your goal is for a voltage of 85V maximum "key up" as described in the text. You can't hurt the amp. If the voltage goes too high, the power supply will fault and shut down automatically. The KPA500 does heavily load a 115 VAC circuit. Most of the drop is likely between your breaker panel and the outlet and, of course, the further from the breaker panel you are the more drop you'll experience. One key point of loss is a bad wall outlet. The spring contacts in the outlet can grow weak over time and not make good contact. Be sure the wall plug fits snugly and does not come out easily. 73, Ron AC7AC -----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]
