[Elecraft] KPA500 Died

[Gary Ferdinand]

Well, I’m hat in hand looking for some advice.  Thanks in advance.

Configuration:  K3, P3, KPA500, KAT500 to a wire.  AUX cable used for control.

Symptom:  K3/KAT500 loads fine into the wire with amp either off or in standby.  SWR goes high and no power out when amp is online.

Possibly interesting facts:

1.   Was toying with the NAQP today.  Seemed ok at the time.  Total failure as I was trying to make a 6 meter VHF contest Q.
2.   Numerous faults in the fault table for excessive dissipation.  Fault code is 11, yet no fault seen on the amp.  News to me.
3.   I’m totally clueless as to how to interpret the fault table timestamp as to date and time, other than most recent at top
4.   Amp is dead on all bands, 160-6  (no power out, presents high swr to k3, relay heard in KAT500 at keying speed)
5.   Tried a full power-off (plug pulled) with no difference
6.   K3 gets the On/Off signal from the amp.
7.   The amp was built by me from the kit and has provided good service for months
8.   Firmware 1.33 on the amp.


There’s a very nice snowdrift out back that I’m considering throwing it into.


Tnx for any suggestions.  Now back to the schematic.  :-(

73/Gary W2CS