[Elecraft] problem with K2, KAT100 and K2100PA combo

[brianpepperdine brianpepperdine]

Due to circumstances, I have a bit of time on my hands..
so I had elected to go thru my rigs here re. possible hamfests or 
private sales.
First thing I decided to look at was my K2 with the amp integrated into 
it and the separate KAT100 tuner connected outboard.

Things seemed fine overall and then I tried to auto-tune on 17m band
It started to tune and then the power went off on the K2.
I think the PA tunes at the 20 watt level (true?) so it should (?) have 
folded back to 20 watts for a 90 watt output setting on the K2 re. any 
high SWR encountered...yes?
In any case, the K2 WILL run when on 12 vdc power fed to the regular 
coax plug feed, but not with the K2 on the regular Anderson powerpole 
input required for QRO operation alongside the KAT100 with its 12 vdc 
feed.

Any ideas what to look for in this situation?
And... I admit I ignored the warning in this case and did NOT use a 20 
amp fuse in the power line to the K2... but it does still run at a QRP 
level with the regular DC supply.

Brian Pepperdine
VE3HI VE3VAW