Problems with a new Fender BandMaster V Series! Uggh!

[Repairguy]

I took a look at your schematics. If it was R73 in the HV power supply that burned open, then that means the "Z" supply got pulled down somehow. This really cannot be associated directly with the power tubes as R61 and/or R63 would have clearly burned open first (unless they too are now open?). If you haven't gotten this repaired yet, I would suggest looking for a short to the chassis of the wire which connects the "Z" supply to these resistors.
The ribbon cable would not withstand the current without melting first. you may be heading down the wrong path thinking it is on the opposite side of a ribbon cable.
Good Luck!

[Wilder Amplification]

I took a look at your schematics. If it was R73 in the HV power supply that burned open, then that means the "Z" supply got pulled down somehow. This really cannot be associated directly with the power tubes as R61 and/or R63 would have clearly burned open first (unless they too are now open?). If you haven't gotten this repaired yet, I would suggest looking for a short to the chassis of the wire which connects the "Z" supply to these resistors.
The ribbon cable would not withstand the current without melting first. you may be heading down the wrong path thinking it is on the opposite side of a ribbon cable.
Good Luck!

R61 and R63 are a lower resistance value than R73. In order for the power to exceed the rating of the resistor, there would have to be enough current flowing through the resistor for the resistor to cause a voltage drop high enough to increase the power with the increased current flow. Well R73 is a 1K while R61/63 are a 470. The 470s would see close to 1/2 the voltage drop that the 1K would given the same amount of current flow through these resistors. Example, throwing random numbers for example's sake, given 441 volts @ 300mA through these resistors, the 1K would see a 300 volt drop across it while the 470 ohm would see a 141 volt drop.

The screens pull the most current from the Z supply than anything else that's hooked up to it. It's also much more common to have a screen short, which could definitely blow that resistor. Wouldn't necessarily mean that the screen resistors themselves would be blown...they could be...the OP never stated if he checked them or not. If it took out the 1K quick enough, the 1K would've acted like a fuse and protected the 470 ohm screen resistors before they had high current flowing through them long enough to blow them.

[Repairguy]

Please keep in mind that the wattage of these resistors needs to be considered. The 1K resistor (R73) in this HV circuit is a 5 Watt wirewound, where the 470 ohm screen resistors (R61 & R63) are 2 Watt metal film. If anything is going to go as a result of a shorted tube, it will be one of these 470 ohm resistors first.
I just had a Deluxe VM in the shop last night, which is basically the same as the Bandmaster VM. It had almost the identical problem as the one described in the original post. The problem seems to be that there are a series of wire jumpers that cross over HV traces with no insulation. Even though they don't appear directly shorted, they are prone arc when the HV is energized. This is the reason for these higher wattage resistors burning open in the HV supply. These jumpers need to be insulated and separated from the PC board. This should resolve the shorting issue originally described.