Interesting - the internal power supply had already been removed from mine by the time I got it.
I had a tech named Terry Wusnack work on it a few years back; he's in LA (where I live) and is a former QAL employee (happy to pass his contact if you want). He gave me an external, +/- 18V DC switching power supply - pic attached, these are pretty cheap - and ran the meter lamps off a separate 28V AC power supply. The bulbs are
Chicago Miniature CM334 GE334.
I honestly might just recommend following suit and moving to external supplies - the one Terry gave me works fine (although I did eventually build myself a linear one) - I remember him also saying that using external PSU helps reduce noise.
Attaching manual here if you don't already have it; it's the one circulating on web, certain schematics are definitely not correct for this model but at least portions of them are accurate - not sure about PSU as I never had reason to check that.
I can eventually get you accurate channel card/buss schematics, though they'll be hand drawn
