Genesis not displaying games properly

[gbpxl]

Genesis 2 VA1. I know for a fact it's not the power or A/V cable because I tried them with a different Genesis 2 and all the games played flawlessly. I cleaned the heck out of both the cartridges and the pin connector. I'm getting 5 VDC coming out of the 7805. There are no obvious signs of damage to the board like leaking caps or broken traces though I supposed there could be hairline cracks in the vias or solder joints. I have yet to go through the painstaking process of checking all my caps. I have a feeling one of the ICs is bad.

So the only cart that seems to somewhat work is my 240p Test Suite cart. Seems fine for the most part but there's sone weird buzzing sound there. Sonic 1 gets to the "Sonic Team Presents" screen and then a garbled red picture with Japanese characters comes up. In Aladdin, after I pass the license screen, a flashing red screen comes up with a black rectangle in the middle. Another game (I forget which) there's a blue screen with a bunch of random codes that look like Game Genie codes and the word emulator at the top. With most of the games I can elsee the license screen but that it goes to a black picture with no sound.

Wondering if maybe my pin connector is too loose. Like if the test suite cartridge is new, maybe theyre using a thicker PCB so it's making better contact? I might look into this

[gbpxl]

I just tightened the pins but it didn't help except now the system has the beloved death grip on it.

I do find it curious though with how the 240p is the only cart that works. Board thickness is the same however the edges on the 240p test suite board are the same thickness throughout, whereas the other carts' PCBs kinda become more narrow.

[Gameguy]

If there's a cracked solder joint, start with resoldering the pin connector to the system board. Not all games use the same pins so that could affect which games work better than others.

Did you inspect all of the system board? Including the bottom by taking it out of the case? Maybe there's corroded traces on the bottom while the top still looks fine.

[megasdkirby]

If there's a cracked solder joint, start with resoldering the pin connector to the system board. Not all games use the same pins so that could affect which games work better than others.

Did you inspect all of the system board? Including the bottom by taking it out of the case? Maybe there's corroded traces on the bottom while the top still looks fine.

This. I would reflow parts slowly and test each one by one. Check any resistors, diodes, capacitors, etc. Reflow the pins under the cart slot.

Do you have a test unit Genesis? You could remove the ICs and test them on another unit to see what happens.