As with the previous Sony Watchman hack, injecting a composite video signal into this one is just as easy. I desoldered both the VIF/SIF IC & the digital tuner control (the tuner controller was still injecting it’s indicator into the video circuitry with the IF IC disconnected).
Composite video is on pin 18 of the Video IF IC, with the audio on Pin 13.
So now each the audio and the video wore you just soldered connect to a ground or is the signal just via a single wire?
Nevermind….I see from the schematics pin 18 (the one you mangled in the other tutorial) is the ground for video. Duh.