[Elecraft] K2 w/KPA100 power resets after approximately 2 hrs of turn-on time

[Vic Rosenthal]

Try checking solder connections in the lowpass filter area of the kpa100, especially the toroid leads. Often bad connections produce temperature-related problems.

Vic 4X6GP/K2VCO 

> On 13 Nov 2015, at 3:27 AM, wa4ywm <wa4ywm at comcast.net> wrote:
> 
> I originally posted this in July and I still have the problem. The issue is
> as described below past the dashed line. Note that the issue happens even if
> I haven't been transmitting.
> 
> Don Wilhelm helped me attempt to troubleshoot the issue. We eliminated the
> base K2 as the source. After that, at Don's suggestion, I installed the
> KPA100 upgrade kit - no success. At this point we gave up.
> 
> Recently I replaced D16 & D17 on the KPA100 after reading about similar
> problems caused by the damaged diodes. Still no luck.
> 
> Has anyone out there had a similar issue? 
> 
> 73,
> Jim Elmore WA4YWM
> 
> ------------------------------------------------------------------------------------------
> 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 the
> supply
> was the source of the problem. Apparently not since the K2 would operate for
> a significant time after turning the K2 back on.
> 
> 
> 
> 
> 
> --
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