ColecoVision, no sound, audio?

[INTVCruise]

Hello everyone, I just received a non functional ColecoVision that I have no idea what to do next. There is no video output or sound, when I flick the power switch the static on the television screen chances a tad bit so it looks like it is receiving power, but I really am not sure. Here is a picture of the screen displayed. It was tested with a known working power supply and video and audio cables. The rf box has a lot of broken solder joints so I went in and applied solder, but there was 0 or very little chance at all. Both channels were tried, 3 and 4, no difference. Also tired cleaning and reflowing the power switch with solder, but no effect at all either. Any suggestions would be much appreciated. 

Edited April 20, 2020 by INTVCruise
add extra info.

[+-^CrossBow^-]

If you want to verify that sound is at least working. Attach a temporary wire off the left leg of C38 near the center rear of the mainboard next to the RF modulator as you face the front of the CV. Attach that wire to the center input of a standard RCA jack and attach another wire to a ground along the CV to the ground/- terminal on the RCA jack. That should bypass the RF modulator for the sound side of things to see if the CV logic is at least doing something. If it is, remember there are delays in the startup screens for most games with the stock bios chip in place. So I would wait like 20 or 30 seconds after powering it on and then press the 1 button on a controller to see if you can get a game to start and hear sounds.

 

if you can, then you are likely looking at a faulty RF modulator itself on the CV. 

 

[ChildOfCv]

Start with measuring the power supply.  The listing of pin voltages should be on the power brick.  Without 12V, the modulator will be dead.  So will video memory, for that matter.