[Elecraft] Fw: Sudden erratic power/high current problems with K2

[Don Wilhelm]

Jeff,

I have never encountered an intermittent diode, but of course soldering 
problems can create  an intermittent.  Also, you might have an 
oscillation that is creating that behavior - it is difficult to say if 
you are only looking at the output power - the actual frequency of the 
output would reveal whether it is a parasitic oscillation or just a 
power control intermittent.

One of the clues is that a parasitic oscillation will usually not show 
up when working into a dummy load because the dummy load is not 
frequency sensitive - when working into an antenna and/or an antenna 
tuner, a parasitic will show up with a high SWR indication because the 
load is frequency sensitive.

If your KPA100 was purchased before Nov 2006, it does not have the newer 
T/R switch design, and you should upgrade it with KPA100UPKT.  If you 
have already done that, be certain that C31 was changed to a 0.22 uF 
capacitor with the upgrade.  The upgrade kit does not contain the new 
capacitor for C31 - you must request one separately from 
parts at elecraft.com.  There are steps in process to include the new C31 
with the KPA100UPKT, but it is not yet complete.

73,
Don W3FPR

Jeff Kinzli N6GQ wrote:
> Don, would this behavior (of zapped wattmeter diodes) be intermittant,
> or constant? I have been chasing an intermittant high-output and
> erratic output problem for a while...just wondering if this might be
> my problem? Are these diodes particularly ESD-sensitive?
>
> Thanks,
>
> Jeff N6GQ
>   
>