[Elecraft] KPA500 failure

[Lyn Norstad]

A couple days ago, I stepped out of the shack for a few minutes and upon
returning found the KPA500 had shut down.  I didn’t note any brief power
outage, and I’m quite sure it was “ON” when I stepped away.

 

It has been a little quirky in keying since that time.  Yesterday it gave
off a funny smell and the Power and SWR LEDs were jumping up and down for no
apparent reason. The  display screen jumps to frequency readout when I key
the exciter, no matter what it is set for.

 

The KAT500 seems to be working normally with the amp either OFF or in
Standby.

 

I did a total power reset and reloaded the current firmware (v01.54), but no
change.

 

I have not pulled it apart yet, but I seem to remember these being the
symptoms discussed some time ago that required an LPF rebuild.  Somewhere
along the line, Elecraft switched to a SM board and that’s when the trouble
started.

 

So my question 
 besides asking for general advice 
 is if anyone knows the
serial number when Elecraft made that change.  My KPA500 is s/n 03835.

 

Thanks!

 

73

Lyn, WØLEN