[Elecraft] KPA 500 Troubles

Andy Durbin a.durbin at msn.com
Thu Oct 16 10:20:59 EDT 2025


"Well, it happened after an accidental shot of 100 Watt power. KPA had an overpower fault which I cleared. Now I cannot seem to key it."

I makes notes of other people's KPA500 misfortunes and you are not the first to toast a KPA500 with gross overdrive.

My notes seem to indicate that R23 on the PA module input is a common casualty.  Various components in the T/R switch can also be damaged.  There is a T/R switch schematic with test voltages for almost every component junction at   https://www.qsl.net/wb4kdi/Elecraft/

Scroll down to KPA500 or use the direct link  https://www.qsl.net/wb4kdi/Elecraft/KPA_TR.html

Click on "Faulty D10" and "Good D10" to see the annotated schematics.

Good luck and please report what you find so others can learn from your misfortune.

73,
Andy, k3wyc



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