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Your tube heaters don't glow, so nothing else will happen.
The power tubes do not run on DC, they are all four in parallel and they run on 6VAC. That 6v supply IS elevated from ground by +24v, but that is not DC heaters.
Get them going.
They are served by that 10A fuse F2. You MUST remove the fuse from its holder to test it, you cannot measure the fuse while still in its clips. If the fuse really is OK< then there should be 6v in the system. Right by that fuse, there should be a two-wire connector from the power transformer - if I recall, the heavy wires are yellow. Is that connector OK? Os ther 6VAC from pin to pin on it? From there, the 6VAC goes through the fuse and on to the ribbon cable from the maion board to the powr tube board. A bad pin on either end of that ribbon could kill the 6VAC to the tubes.
DOn't measure voltages to ground, measure voltages across the heater pins at each socket.
The preamp tube heaters are on a totally separate circuit from the power tube heaters. There are four preamp tubes, heaters wired for 12v and in series across the +24vDC and the -24vDC. In other words four 12v tubes in series are wired across the 48vDC made by the +24 and -24. ANy interrpution in that string will darken them all.
Most likely interruption? Open R47,R49. This pair of 22 ohm flame proof resistors in top center of page 2 of the schematic, and they are right in the corner of the preamp tube board. While it is possible, open heaters on 12AX7s are extremely rare, and those resistors being open far more likely.
If you want to follow the preamp tube heaters, look at page 2 top center - the connector to the right of V4 phase splitter tube. See +24v come in there, adn go right to the two resistors, out the left end of them to FIL. Now back to page 1, upper left. See FIL applied to pin 5 of V1. Now follow the current from pin 5 to 4 across the row of three 12AX7s until you come out V5 pin 4 to FILI. Now back to page 2 to find FILI just continues the string through V3 and out of that to the connector we started with and the -24v rail.
The power tubes do not run on DC, they are all four in parallel and they run on 6VAC. That 6v supply IS elevated from ground by +24v, but that is not DC heaters.
Get them going.
They are served by that 10A fuse F2. You MUST remove the fuse from its holder to test it, you cannot measure the fuse while still in its clips. If the fuse really is OK< then there should be 6v in the system. Right by that fuse, there should be a two-wire connector from the power transformer - if I recall, the heavy wires are yellow. Is that connector OK? Os ther 6VAC from pin to pin on it? From there, the 6VAC goes through the fuse and on to the ribbon cable from the maion board to the powr tube board. A bad pin on either end of that ribbon could kill the 6VAC to the tubes.
DOn't measure voltages to ground, measure voltages across the heater pins at each socket.
The preamp tube heaters are on a totally separate circuit from the power tube heaters. There are four preamp tubes, heaters wired for 12v and in series across the +24vDC and the -24vDC. In other words four 12v tubes in series are wired across the 48vDC made by the +24 and -24. ANy interrpution in that string will darken them all.
Most likely interruption? Open R47,R49. This pair of 22 ohm flame proof resistors in top center of page 2 of the schematic, and they are right in the corner of the preamp tube board. While it is possible, open heaters on 12AX7s are extremely rare, and those resistors being open far more likely.
If you want to follow the preamp tube heaters, look at page 2 top center - the connector to the right of V4 phase splitter tube. See +24v come in there, adn go right to the two resistors, out the left end of them to FIL. Now back to page 1, upper left. See FIL applied to pin 5 of V1. Now follow the current from pin 5 to 4 across the row of three 12AX7s until you come out V5 pin 4 to FILI. Now back to page 2 to find FILI just continues the string through V3 and out of that to the connector we started with and the -24v rail.
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