Last night I BEAT
the RCA 8TS30 into submission. Replaced the faulty contrast control. Hooked up my B&K 1075 and tried injecting signals throughout the IF and video stages. Nothing. Suspected the AGC was still messed up. So traced the circuits back towards the tuner from the contrast control. Tested a few resistors along the way (all tested within spec) and finally came to a 270pf mica cap AT the tuner. I usually ignore micas, but decided to replace this one for the hell of it. BINGO!!! That did it. When I turned the set back on, I got normal looking snow instead of just a white raster and the contrast control was finally having the proper affect when adjusting it. Flipped on my B&K and just hooked it up to the antenna leads on the set and got decent picture and audio. I had to tweak the IF cans a bit to match up best picture with best audio while fine tuning, but FINALLY!!!!! Set was on for about 2 hours and seems solid now. This set is going back in its cabinet tonight and waiting for its owner to come get it in a few weeks. Below is a video of the set playing last night.
https://youtu.be/nr8OWvYUOWY