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PostPosted: Sun Feb 11, 2018 8:28 pm 

Joined: Tue Oct 24, 2017 11:07 pm
Posts: 26
I got a Famicom a couple weeks ago and figured I should AV mod it because it's a pain changing my VCR from AV in to channel 95 whenever I wanted to play on it (having to hit the "channel down" button 30 times gets old). However, my stupid ass shorted out ground and VCC with a strand of solder wick during the modification process. Initially, I thought the system was still working but that's sadly not the case. After the console's warmed up (~10-15 minutes), the console starts doing the stuff in this video (note that if you're wearing headphones, my phone's microphone REALLY loves the sound of the Famicom's power switch and me removing carts so you might want to turn the volume down, the sound works fine on the system).
Tech info about the games I'm showing:
1. Some mahjongg game I forget the name of, it has a MMC1 and 8K CHR RAM- Seems to work fine but with graphical corruption
2. Super Mario Bros (UNROM)- Freezes on title screen
3. Clu Clu Land (NROM) - this one's interesting to me since the collision detection on the field is screwed up by the graphical corruption, so I don't know if the game is looking in VRAM to see if there's a tile there or if it's a WRAM problem.
4. Mother (MMC3)- This one isn't glitchy in the video but has been in other testing, freezes after the title screen
5. Super Mario Bros (UNROM)- Works this time but is extremely slow along with the graphical glitching. I remember reading on the wiki that SMB has all the gameplay code in the VBlank interrupt so maybe the slowdown is due to the PPU not sending the interrupt or the CPU not receiving said interrupt, who knows.

If anyone knows what I could look at being the problem here, I'd really appreciate it.

PostPosted: Sun Feb 11, 2018 8:38 pm 

Joined: Sun Apr 13, 2008 11:12 am
Posts: 8488
Location: Seattle
SMB is known to load its title screen from CHR-ROM.

It looks to me like some of your PPU address lines are shorted together.

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