ToyFlashback

I recently found a Stunt Cycle model SC-450 at an estate sale. The box and console were in very good condition, but the good news ended there. When turning On the console it does take the TV from snowy to solid black, but then nothing. No Sound and No other Video comes up. Searching for repair info online only turned up in depth detail of the arcade cabinet, but nothing to help with my home unit. I tried opening up the unit, and everything was surprisingly clean. It has the identical AV cable as my 6-switcher Atarti 2600, so I swapped that and same issue. Then removed heat shields. Nothing to me jumped out as looking faulty, or giving indication of what to try next. I am hoping one of the far more experienced people here might have some advice based on my description and photos. Thanx for your time.