[Elecraft] KPA 500 Troubles

[john simmons]

Thanks so very much for posting this! I did note that several links under "Upgrades:" return a 404 error.

73
-de "Curly" John NI0K
QRZ.com<https://www.qrz.com/db/ni0k>
Hams Over IP<https://hamsoverip.com/> call me: 101468

On 10/16/2025 9:20 AM, Andy Durbin via Elecraft wrote:

"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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