Has anybody else in here had an Ameritron ALS-600 develop low power output over the years and successfully repaired it? Caveats: NOT bad finals, NOT a bad swamping resistor Mine is currently only putting out about 150 watts on 160 meters, and increasing up to about 400 watts out on 10 meters nearly linearly as I progress from 160 meters on up to 10 meters. Driving it with an ICOM 756 Pro II. About 60 watts input in all cases, about 20 amps input from the transformer power supply in all cases. Anything more than 60 watts input increases current input, but not power out. My transformer power supply is at a clean 55 volts DC unloaded (and pretty much stays there loaded). When I first looked at this amp, bias's on the MRF150s were ranging from 80 mA to 170 mA on each MRF150 and adjusting those to 250 mA had no effect. Replacing the MRF150s and adjusting to 250 mA had no effect. The datasheet test setup is set to 250 mA. Ameritron suggests setting them to 300 mA. I just can't believe bumping them up another 50 mA in bias is going to change anything--or has anyone actually seen going from 250 mA to 300 mA bias in each of the 4 MRF150s actually increase power out? And I have already replaced the swamping resistor (it was a little outside the 10% tolerance). Still no change. Cleaned relay contacts. No change. Tracing the RF path, I see there are several discrepancies between the schematic provided by Ameritron and the amp itself. Nothing obviously burned. Anybody else have any experience with this? I'm at a loss of what to do next. Can't really take measurements under full power. Can't test the capacitors in circuit with power off. Anybody?