Sega Megadrive Model 1 rf output problem

[Snow_Cat]

Your video seems to show normal brightness/signal level, however the image goes out of sync in exponentially timed bursts of noise.

I'm guessing that for your unit

1. the sound is unaffected
2. that the game plays normally otherwise
3. you are using RF (cable) out and that changing the selected channel out, using composite, or RGB output doesn't solve the problem

Looking at emudocs.org - Genesis leads me to ask two questions:

R16 (2.2k) on the line from pin 8 of IC 8 (YM-7101) to pin 10 of IC 13 (CXA-1145) to pin 7 of CN1 (DIN-8)
Has this resistor has blown open?
If so then it would not pull up the line and the natural capacitence will gradually charge up obscuring the sync pulse. This would produce a series of decreasing periods of 'normal' operation interspaced with consistent bursts of uselessness, eventually leading to a state of complete uselessness.

Can we see what the capacitors under the RF shield look like?
There are also a few loops that are used by IC 13, and if one of these has gone off then it could also be throwing off the timing.

edit:grammar Could/Would. -s instead of -ed and -ing... I think it's time I ate something.