K2 w/100W amp has temperature related xmit shutdown

Posted by wa4ywm on Jul 05, 2015; 11:28pm
URL: http://elecraft.85.s1.nabble.com/K2-w-100W-amp-has-temperature-related-xmit-shutdown-tp7604669.html

I have a K2 serial no. 4729 with the 100W amp which I have been using for almost 10 years.

It recently developed a problem with the following 2 symptoms:

1. After operating for some time (perhaps 1-2 hours) the Tune function will begin to display 1 W with a 1.0-1 SWR on all bands. It normally displays 22-23W with the correct SWR shown.

2. At the same time, if I attempt to transmit, the K2 will apparently begin to draw too much current and it shuts down and re-starts. The Tune function also shuts the K2 down at this point.

I observed the same behavior on a dummy load - to eliminate an antenna or feedline issue.

I also left the power supply on while letting the K2 cool down to see if it was the source of the problem. Apparently not since the K2 would operate for a significant time after turning it back on.

I have not tried any other troubleshooting. I thought I would see if anyone could point me in the right direction before I took the shotgun approach.

TNX for any help & 73,
Jim WA4YWM