I've just acquired a Genesis Model 2 unit. Cleaned it up a bit. I'm using the AV cable and when I flip on the power, the screen goes from the blue "no signal" for the tv to black but that's it. Any advice on where to start on this?
I hear the 7805 can cause these issues. Could also be the caps in it. Try a complete cap replacement first. What cable are you using? Composite Video, RF, or RGBS cables? If you are using RF then try a new cable.
Right now I'm using the composite video cable. Caps? Any suggestions as to which ones to swap first? I take it that there's some sort of writeup on this.
Replace all of the caps in the console. I'm not sure what values they all are but I'm sure someone on here can send you a list or a kit.
Sometimes the Z80 chip shits the bed and black screen occurs. No known cure besides swapping it for another Z80.
Just a few days ago i had the same issue. The main chip had a broken connection. When i pressed on it gently it would boot just fine. Reflowed the chip and now it is just fine.