IIRC it took me a month or so to do my 1000A. Mainly problems with the MPX board, which turned out to be a bad (cracked) trace on the board under one of the pots, and you couldn't see it unless you removed the pot.
ONE thing I DID notice on my 1000A. There are 3 - 6AQ8 tubes. 1 for the RF-AMP, 1 for the Muting Circuit, and the last one on the 19kc amp section of the MPX. 6AQ8's are run hard and put away wet. And they avg. $18.00-$22.00 each. The primary substitute for the 6AQ8 is the 6DT8. Avg. $3.00-$5.00 each. The point of all this is that a 6AQ8 is MANDATORY in the MPX. A 6DT8 will not allow the MPX to work correctly. However 6DT8 in the RF-amp, or Muting circuit is FINE.
If you are going to go with NEW STOCK OUTPUT TUBES, I'd recommend the TUNG-SOL 7591 Re-Issues as 1st choice, with the EH7591's coming in 2nd. JJ's come in DEAD LAST! Even below worn out, .22 target old stock tubes. I got a quad of them (TungSols replacing my EH7591's for use in my 800-C's) and they really help the 1000A stand up and smack you in the face. Run them at 75%-80% of Max dissipation (reset the bias to get 14.25W to 15.2W). 19W is max dissipation.
For Example if your Plate voltage is 470V, then you'll need to adjust your bias to between .030 and .032
Divide 15.2/470=0.03234ma Round off to .032
Divide 14.25/470 = 0.03031ma Round off to .030
Use your actual plate voltage and do the math, and adjust accordingly. Mine tend to like the upper end of the settings.
If yours is a single bias pot unit, avg out the quad to .031 (matched pairs are recommended)
If it's a 2 pot, avg the pair out to .031 (matched pair is recommended)
If it's a 4 pot, set each individual tube to where you want.
There is a 4 adjustment board (DIY) that is used on FISHER 400-500C-800C's that works well on the SANSUI. I built one for my 1000A and it works really well. Go to the FISHER Forum and search "IBAM". It might be in the STICKY Thread called "COMMON Parts for FISHER's".
Measure the mA across the 10ohm resistor on each pin 5 (one probe on the tube side of the resistor, one probe to any chassis ground).