Marshall JCM800 reissue DEAD?

[glp]

Got a bit of a head scratcher?? This one blew the filament resistors and the hum balance pot (shorted power tube). So replacing them was no HUGE deal (even though I couldn't find an exact replacement for the Hum Balance pot - and would still like to find one).
Anyway, plugged it in....... DEAD! Not finding any voltages on the Mercury Magnetics PT I had installed a few years earlier, I sent it back to Patrick and they tested it as good!
Reinstalled it last night. I get 120vac at the power cord. 120vac at the power switch but I don't get ANYTHING at the standby switch from the PT Output and no filament voltage either? Which is what lead me to believe the tranny was a goner in the first place? The rectifier diodes test good, in circuit.

But I am a bit befuddled?? Hard to imagine anything down circuit would prevent the PT from having measureable voltage and the standby switch tests as good.
This is probably so simple it is right under my nose and I can't see it or ???

Appreciate any comments

[sluckey]

Reinstalled it last night. I get 120vac at the power cord. 120vac at the power switch but I don't get ANYTHING at the standby switch from the PT Output and no filament voltage either?

There is still a voltage selector switch between the power switch and the PT. Do you have 120VAC directly across the PT primary?

[LHPcope]

This sounds simple, but are you able to read other DC voltages with your meter?

If the meter passes, do you have H.V. at the input to the standby switch with it in the open position?  If not, do you have H.V. ac on the output of the PT with the rectifier diodes out of the circuit?  Do you have filament voltage from that transformer tap disconnected from the filaments?

Do you have an appropriately low resistance reading on the input and output to the PT with it disconnected?  If those readings are good connect and disconnect a 9 volt battery from the PT input and see if you see a voltage pulse through the PT, this should verify that the tranny is good.

I hope this helps,

[SILVERGUN]

How about fuses?

[sluckey]

Since there is no HT voltage OR filament voltage (probably no bias voltage either     ), my guess is something in the primary circuit. There is voltage on the power switch, but does it actually get to the PT primary?
 
Here's the schematic. Hopefully the right one...

[Jack1962]

Do you have high voltage on the PT's secondary's , if not your PT is bad