Famicom with scrambled graphics

[Jet Black]

Hello,

I have problems with my newly acquired Famicom, on all games I have scrambled graphics like this:

http://i.imgur.com/G1vK5Fm.jpg

The background graphics are a broken mess, the sprites look fine though and the sound works without problems.

The Famicom worked totally fine after I did an AV-Mod, I could play Rockman 3 for a few minutes. After that I tried a Pal Mega Man 2 with a NES-to-Famicom pin adapter, it ran fine for 10 seconds then the graphics glitched out.

I already tried cleaning the cartridge connector and reflowing its pins, but no success. The mainboard looks ok optically.

Doe anyone know how to fix this?

[Pasky]

Looks like maybe the latch is faulty.

Take a picture of Journey to Silius title screen if you have it.

[Jet Black]

Unfortunately I don't have Journey to Silius, and no Everdrive either

The games I have:

Famicom
Rockman 3
Ninja Ryukenden
Batman

Also following PAL B NES games, but I am quite hesitant to use the pin convertor again right now:

Castlevania 2
Mega Man 2
Shatterhand
Guardian Legend
3in1 cart with Tetris, Mario Bros. 1 and Nintendo World Cup

[Pasky]

Ya I'm unsure by that picture alone, is it always the same garbage? It could be the latch, or maybe some faulty ram. Possibly the PPU as well, the CPU seems to be fine if games are playable and you're getting audio.

[Jet Black]

I am able to get a slight different garbage, when I wiggle the cart quite hard in the slot. But on boot it's always the same broken graphics as shown in the photo.

[Pasky]

Well if it's locking up, it's either bad ram or a bad PPU. My money is on the RAM as I've had a couple go faulty, never had a bad PPU that wasn't destroyed by user intervention.

[Jet Black]

Thank you, two other guys on another forum said that the ram must be the cause of the problem, too.

Which chips have to be replaced exactly?

http://i.imgur.com/wGGRGZd.jpg

Something special I need to know, when I want to buy them?

[Pasky]

U1 and U4 are the ram, they both may need replacing but it's possible only one of them is bad.

[Jet Black]

Where can I buy these chips? Looked on eBay, but the chips seem to have a different size.

[Ed Oscuro]

They aren't made any more so you might not have any luck finding them at a good price (and if you do find some, there's no guarantee they're working). If you're desperate, you should be able to get by with larger DRAMs with the same form factor. Good thing FCs are cheap

[Jet Black]

Oh well, is this one compatible?

http://www.buyicnow.com/it.php?i=636