[earlyfilm]

First verify that your rectifiers are 5U4's and the damper is a 5V4, which is a rather unusual choice for a damper.

Yes, pull both at the same time. A shorted damper can kill a new horizontal output tube and I normally yank both together. The multiple tube pull method won't work on stacked power supplies, but the stacking is limited in this set.

If the voltage across the resistor is as high as before, immediately kill the power and feel all electrolytic caps.

Don't worry about the HV, as it wont be working, but don't touch the chassis and an electrolytic at the same time as some might have lingering B+. If one is heating, check for incorrect wiring, ratings and polarity on the hot one(s).

If no electrolytic is heating, print out the RCA Factory Schematic and Wiring diagrams from the RCA 8TS30 PDF on ETF and give them to your son and offer him a reward if he can find your wiring error starting from the Power Supply and Reaction Scanning (damper) tubes. The wiring error could be something as simple as a tube in the wrong socket . . . . . or a grounded floating ground . . . . or an electrolytic with polarity inverted.

Jas.