Okay. I finally got to take some measurements when it was acting up.
Red wire at filter can +43V
Green wire at filter can -43V
Red wire from input board to power amp board +8V
Green wire from input board to power amp board -8V
Q12 at the collector +43V
Q16 at the collector -8V
Q5 at the collector +43V
Q6 at the collector -43V
I'm not sure which one on the bracket is Q18 and which one is Q19 but when looking down at the bracket from behind the chassis
Left transistor Red Wire +43V Blue wire -27V yellow wire -27V
Right transistor Red Wire +27 Blue wire -43V yellow wire -43V
Not sure what else to measure. Does that give you any ideas?