I finally caught the station ID and it's 107.9 FM which is a very strong station. Subtracting 42.5 (21.25 MHz audio IF carrier) results in 65.4 or almost the 65.75 audio carrier of channel 3. Thanks for solving that mystery
The waveforms on the cathode of the HOT and damper are dead on both in frequency, shape and amplitude.
So even though I had previously tested the flyback, etc. inside the HV cage, I decided to take another look. Right away I noticed this mica cap between lugs #1 and #4 which does not appear on the schematic.
I compared it to another 630TS chassis and there's no mica cap here but a paper cap has been added. Hmm, I think I'll remove that mica cap and recheck everything.
