My CTC-16XL Project.

[Electronic M]

Try wiggling the IF tubes. If the first IF gives pix noise and or sound noise then the problem is in the tuner if not it is in or before the lowest IF tube number that gives noise when wiggled. Another possibility is the AGC is missadjusted or broken....In that era of RCA the AGC checks the sync level in the video signal every horizontal pulse and adjusts the tuner and IF gain (by changing the grid bias of the tuner and IF tubes) to hold the video level constant.... the AGC control should be able to take the set from blank raster with no signal passing through to normal signal then on to excessive overdriven video that won't sync.... circuit failure can hold it in an exterme state.