SNES CPU Troubleshooting

[Edwgamer]

Hi everyone. I just recently got an SNES from Goodwill with 6 games included. 4 of these games work perfectly, audio and video included. Two of these games, Super Mario World & Top Gear, however, don’t. In both cases the audio plays perfectly fine, but the only video shown is the initial boot up screen (“Nintendo Presents” and “Kemco Presents” respectively). After that it is just a pure black screen with audio playing in the background. I have absolutely no idea what the issue would be, especially because my other games work perfectly fine. I posted on the r/SNES subreddit and someone responded that they had a similar issue and deduced that it was something involving their CPU. This had me worried because I have a very beginner level amount of skill in repairing electronics. Does anyone know if this diagnosis is correct/if I should attempt to repair or just buy a new console? Thanks in advance for any help

[Tanooki]

Did they actually detail why it was the CPU?

 

I'm only asking this because the two games you brought up, they're super common games and don't really push or tax the hardware, they run common as they're sold common.  They don't get into some weird obscure CPU triggers or GPU(PPU) triggers of visual modes that could tick off a damaged chip.  It is also a case of the launch game from them, and a third party title, being SNES games is all they have in common.

 

Don't know what the others are, but they work it appears.  Maybe the games are damaged.  Have you done some level of cleaning, with what, how far?  I want to say the SNES isn't the problem for now or the other games would exhibit issues too.

[Edwgamer]

From the post, they basically said that they had a similar SNES that couldn't load Super Mario World and would go through the same steps that mine did (boots as "Nintendo Presents", goes to black screen with opening music and no sound effects). This person said that they assessed the issue by using a flashcart with a burn-in test cartridge rom on it and saw that it was getting ticked off via the "expanding circle" effect in the graphics test. They then concluded that it was a CPU issue.

 

Top Gear, the other game that also fails to load past the opening credit screen, also uses an effect. Instead of a circle, the logo spins in from the background. 

 

The other games I had to test were Monopoly, Super Caesar's Palace, Vegas Stakes, and the Super Gameboy Adaptor. None of these games, to my knowledge at least, have these kind of effects. I'll be able to clean the games later tonight, so I'll keep you updated if anything changes.

[jeffythedragonslayer]

Did you ever get this SNES working?