Unfortunately, I failed to understand a lot of the information on the Shmups board.
Go back and read again. I also got very confused when I first read that thread. Also, it is over 100 pages of fairly random RGB modding of different sets, so difficult to digest in one sitting.
Most people said it was too old of a model and that I would need to do a mod on the hot part of the chassis,
There is no need to mod anything on the "hot" part of the chassis.
I've been looking at a schematic for the Sony 1926R.
The TV's jungle chip is CX20192. Can't find any datasheet on this chip, but seems to have no video inputs apart from RF. You might have some success injecting RGB via pins 17,18,19 which are the RGB outputs to the neckboard. Probably should use a video amp the RGB as it looks like schematic says it should be ~3.0 to 3.8vpp with a 1.9v average.
You could buy a video amp from Ultimarc or similar. With 75R resistors in series on the RGB outputs and 75R termination (to TV ground) resistors at the TV end, voltages would be about right. You could also try swapping the 75R resistors in series for pots (100-200R range) and precisely dial-in the voltage levels.
Not sure what to do with sync, maybe inject it to the jungle via pin 28 (which I think is where the RF video input normally goes).
I note that the OSD/text support chip on the TV only inputs to the green signal (pin 17), so RGB input via OSD method is not feasible.
Disclaimer: Neckboard RGB mods are a poorly understood method, so not much info out there. I've never done one myself, just throwing ideas out there.
Just throw it out and replace with a TV that works properly and has better documentation.
This-
Apart from an rgb mod, trying to use most Sony TVs is a PITA unless they have component input.
pbj has a talent for stating what everyone else is thinking. You'd have an easier time with another cheap or free TV, or an arcade monitor. If you are planning to showcase a game you are developing, it would be worth it.