a few more tests:
the 123v (B+ feed to the line stage) output of the psu transformer
never reaches more than about 50v, even unloaded. all the others have
negligible volts on. could i802 be the cause?

here's a part of the psu schematic: http://www.fileden.com/files/2007/6/...380%20psu.jpeg

I'm all ears to any suggestions.
B