[Elecraft] K2/100 Upper bands - power output problem

[Scott Martin]

I just finished building a KPA100 last week and it has been running fine
until...

Today, I suddenly can't get anything over 50 watts out of the upper bands
(20 - 10 meters). Power output also gets a little less as I move up from 20
with the worst being 10 meters at ~30W. 30 meters on down to 80 are all just
fine and pumping out 120 watts when asked to do so. I have checked all diode
voltages and all seems fine. Indicated power out tracks the external watt
meter perfectly right up to 50 watts and that's all she wrote. I have a
feeling I have a bad solder joint or toroid problem someplace, but not sure
where to start looking. I'll pull every toroid in this thing and re-tin them
if I have too, but I was hoping someone here would be able to point me at
something obvious that I might be missing.

I've been working this one all night and I'm outta gas...
I sure could use a hand... Any ideas?

Thanks,
Scott
AG4KU