DThomasC
Senior Member
Nuuska could be on to something. I still want to verify that one of the output tubes isn't pulling much more current than it should be.
V4:
2 = ( pin 3 to 2 = 0 )
7 = ( pin 3 to 2 = 290 )
9 = ( pin 3 to 9 = 290 )
V5:
2 = ( pin 3 to 2 = 0 )
7 = ( pin 3 to 7 = 0)
9 = ( pin 3 to 9 = 0 )
Oddly, with tube 4, simply touching the pins with the positive lead changed the hum amount. I have looked at the solder spots and don't see any cracks. It changes even if I lightly touch any of the three. I also get higher values if I use chassis ground rather than pin 3.
I was thinking the tall tubes, V1 and V2 were the output ones and the three short guys, V3-V5 were preamp and "soak". Still, for some reason one tube is not getting signal, when they all should be doing something.
Volts across the red wires, unplugged from board = 168 VAC. Plugged into board = 157 vac
Volts across the green wires, unplugged from board = 6.25 VAC , Plugged into board = 2.45 vac
DCV at D4/D6 junction = 407
QC2 = 407
Red wire to output transformer plugs onto QC2. = 407
Red to brown = 85ohm
Red to blue 93 = ohm
Pins 7 on both tube connectors is 407 volts, either from pin three or chassis ground. However, measuring with my Fluke meter, it is unhappy and just flashes like some odd over range is happening.