Hey folks,
Long-time reader, first-time poster here! I posted this at KLOV and it was suggested that I try here as well. I have searched for possible relevant threads, but nothing quite matches this, so here we go...
I have recently acquired a Neo Geo MV-1 PCB, and a Metal Slug cartridge. I tested it fine for about an hour one day, and the next day vertical lines appeared on the sprites. See the attached screen image. Here is the troubleshooting I have done:
The cartridge and slot contacts are clean.
I removed the cartridge slot PCB from the metal bracket and cleaned the white plastic connectors with blown air and some alcohol. They were somewhat dirty.
I have not opened the cartridge yet. The cartridge exterior is in excellent physical condition, and I don't want to damage the hololabel if possible. I currently do not have another cartridge to test... but I am looking to get one.
The service menu (without a cartridge) looks normal. (not surprising, as this is almost certainly a sprite / C ROM issue and the menu doesn't use sprites) Similarly, the FBI warning is fine.
Here is the interesting part: Touching a single pin (with a finger, under the board) that goes to the cartridge slot mostly clears up the vertical lines. With some continuity testing (using a multimeter), I confirmed that this particular pin is connected to pin C12 of the NEO-ZMC2 chip. See the attached composite photo, and this video:
https://www.dropbox.com/s/e5cvcvetj343q99/metalslug.mov?dl=0
Perhaps unrelated: There is a wire / solder patch on the board that connects the EDGE pin of the LSPC-A0 to (I think, but not confirmed) the corresponding EDGE pin of the NEO-ZMC2. For some reason, it is routed through an unused OR gate on the a 74LS32P (quad OR). Again this is possibly unrelated, but I am curious about it. See the attached image.
Do you have ideas for further troubleshooting or know a possible cause / solution? Thanks!
Some references:
https://wiki.neogeodev.org/index.php?title=Graphic_glitches
https://wiki.neogeodev.org/index.php?title=NEO-ZMC2
https://wiki.neogeodev.org/index.php?title=LSPC-A0
Long-time reader, first-time poster here! I posted this at KLOV and it was suggested that I try here as well. I have searched for possible relevant threads, but nothing quite matches this, so here we go...
I have recently acquired a Neo Geo MV-1 PCB, and a Metal Slug cartridge. I tested it fine for about an hour one day, and the next day vertical lines appeared on the sprites. See the attached screen image. Here is the troubleshooting I have done:
The cartridge and slot contacts are clean.
I removed the cartridge slot PCB from the metal bracket and cleaned the white plastic connectors with blown air and some alcohol. They were somewhat dirty.
I have not opened the cartridge yet. The cartridge exterior is in excellent physical condition, and I don't want to damage the hololabel if possible. I currently do not have another cartridge to test... but I am looking to get one.
The service menu (without a cartridge) looks normal. (not surprising, as this is almost certainly a sprite / C ROM issue and the menu doesn't use sprites) Similarly, the FBI warning is fine.
Here is the interesting part: Touching a single pin (with a finger, under the board) that goes to the cartridge slot mostly clears up the vertical lines. With some continuity testing (using a multimeter), I confirmed that this particular pin is connected to pin C12 of the NEO-ZMC2 chip. See the attached composite photo, and this video:
https://www.dropbox.com/s/e5cvcvetj343q99/metalslug.mov?dl=0
Perhaps unrelated: There is a wire / solder patch on the board that connects the EDGE pin of the LSPC-A0 to (I think, but not confirmed) the corresponding EDGE pin of the NEO-ZMC2. For some reason, it is routed through an unused OR gate on the a 74LS32P (quad OR). Again this is possibly unrelated, but I am curious about it. See the attached image.
Do you have ideas for further troubleshooting or know a possible cause / solution? Thanks!
Some references:
https://wiki.neogeodev.org/index.php?title=Graphic_glitches
https://wiki.neogeodev.org/index.php?title=NEO-ZMC2
https://wiki.neogeodev.org/index.php?title=LSPC-A0