Hi Bill -- Sorry about missing the minimal sound issue, so again, a couple of comments:
1. If your filter cap is only rated at 450 volts, then a better way to go would be to leave R93 at its original value, and now add an additional resistor between the output of the rectifier tube (pin 3) and C45-A/R93. The exact value will need to be determined by trial and error as it cannot be calculated with simple Ohms Law -- but the value will likely fall into a range of 250 - 500Ω +/- and should be rated at 5W or more. The resistor's value should be determined so as to produce 390 vdc (or close to it) at C45-A. That way, you won't have to change out C-45 if section A is in a new can you had made or bought.
2. As for the little to no sound, make sure that the dummy plug is installed into the Remote Control socket on the rear of the chassis. It is required for there to be any sound produced from the unit if the actual remote control unit is not connected. Sometimes these will be missing. If so, there will be no sound, and you will need to install the appropriate jumpers at the socket inside the set to emulate the missing dummy plug. If needed, the jumpers should be connected between pins 1&3, and between pins 6&8.
Let us know!
Dave