[Amps] Amp Supply LK800 trouble

[kk2ed at comcast.net]

Good afternoon,
I am still trying to help a friend get his LK800A amp going.  Last visit, we thought the 1000pf plate blocking doorknob was bad and not passing RF, as the amp would draw 1A + of plate current, but no RF was appearing at the output. The plate and tune caps seemed to make no difference when tuned.
Well, fast forward, and we replaced the 1000pf doorknob cap.  Now, we are seeing about 500w make it to the antenna, and the Plate tuning has some effect, and max power does in fact equal min plate current (dip), give or take a few ma.   However, the loading control is having ZERO effect, and is affecting the output.  
Close inspection revealed no signes of bad connections or arcing.  We bypassed the vacuum relay to rule out relay issues, and ohm-ed out the tank coils and bandswitch. 
Studying the schematic and checking the components, everything looks good. The circuit is quite simple - plate bypass cap from the plate choke, tapped coil, load/tune varicaps, then the relay.  I'm missing something somewhere...  
We also pulled the three tubes, tried a spare set, same results. Also tried one at a time, same thing, so I think the tubes aren't an issue.
Any ideas?
Thanks
Eric KE2D
KE2D