Been a few months since I worked on a 4-slot, this one has been sitting in a buddies box of broken stuff for a while.
Looks like battery damage, but no watchdog for once which is a nice change
So it is booting, won't boot games, I'm thinking it probably wants to give me a RAM error (stock bios and diagnostics bios)
But somewhere between the RAM error being generate and the graphics being drawn the screen is covered in garbage so I can't read the error, also the nature of the graphics glitch changes after about 15 seconds, if it was just a bad trace it might be stable, guessing it could be a bad chip. Behaves exactly the same way with no cart, and with no top-board at all
So from what I can see the garbage graphics are being drawn very late in the graphics chain
1) Trace the graphics error and fix that so I can read the error messages
2) Read the error message and fix it
So im suspecting NeoB1 at the moment
Any thoughts or ideas before I start beeping out all 160 of its miserable pins?
Looks like battery damage, but no watchdog for once which is a nice change
So it is booting, won't boot games, I'm thinking it probably wants to give me a RAM error (stock bios and diagnostics bios)
But somewhere between the RAM error being generate and the graphics being drawn the screen is covered in garbage so I can't read the error, also the nature of the graphics glitch changes after about 15 seconds, if it was just a bad trace it might be stable, guessing it could be a bad chip. Behaves exactly the same way with no cart, and with no top-board at all
So from what I can see the garbage graphics are being drawn very late in the graphics chain
1) Trace the graphics error and fix that so I can read the error messages
2) Read the error message and fix it
So im suspecting NeoB1 at the moment
NEO-B1 - NeoGeo Development Wiki
wiki.neogeodev.org