Back to the TDA3505 again.
I followed the composite signal on my scope all the way to the TDA3505.
I also checked sand castle going into the TDA3505.
Both look good.
No modulation on RGB lines from the TDA3505, just a fixed DC voltage of around 2V (going from memory).
TDA3505 also seems to be grounding the 1-5V from the brightness and contrast circuits. I see a fixed .8V on those lines when I should see an adjustable 1V-5V. VCC also shows .8V which is really suspicious since it matches the contrast and brightness pins.
There is a 4.8K resistor between 12V and VCC pin 6, and I do see 12V going into the resistor, but .8V on VCC. Resistor tests good.
Everything connected to the TD3505 tests good. Chip shorted again? I'm not very familiar with how this chip works so I'm not sure if it's in a cutoff state or if it's just dead.
I ordered another chip from a different seller just in case, it's possible I got a bad chip from ebay.. wouldn't be the first time.
I did check EVERYTHING else in the schematic, section by section, and found everything working correctly, and all expected voltages to be correct, except for TDA3505.
Also, shorted the first set of RGB output transistors fed by TD3505, and the guns came on, so TD3505 is definitely offline or dead.