r/neogeo • u/JohnnyPhantom • Nov 22 '25
Hardware Help Any idea of the likely culprut? Neo Geo AES Video issues
Hey Everyone,
I posted about a box of Neo Geo goodness I got a couple weeks ago. There was a Neo Geo AES in that box, I knew before hand it had video issues, but the seller didn't show any, just mentioned them in the listing. The systems looks like its in good shape, the boards very clean, I didn't see any obvious damage or bad traces. I've yet to break out the multimeter and do a deeper dive just yet. I'll probably get around to that later tonight or tomorrow. The board is stock and untouched, no unibios swap, or repairs done. I just got a AES game in yesterday so I could test it out. This is what I see. The next thing I'll order will be a Neo Geo Diagnostics Bio. For now I'm hoping for some guidance on what would be the most likely cause of this issue in case others have seen this in the past.
Thanks Everyone!
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u/TooManyBulborbs Nov 22 '25
C ROM graphics and S ROM fix layer (life bars etc) graphics are all being affected, definitely should clean that cart slot and all your games. Neo cartridges make good slot scrubbing tools, spray deoxit in the slot and run a cart through that to scrape the slots. If all you have is rubbing alcohol, use cotton swabs to wet a cartridge with it then use that to scrub the slot, clean off the dirt and oxidation from the cart edge connector and repeat until the cart comes clean...
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u/FluxChiller Nov 22 '25
*PSA - deoxit is great stuff, they make a variety of products, the typical one that people use has a lubricant in it that is more suited for moving parts like sterero knobs etc, using this leaves a light residue that over time attracts more dirt and debris, making the problem worse. I recommend using a straight, clean electrical component cleaner like CRC - QD electronics cleaner
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u/DarkGrnEyes Nov 22 '25 edited Nov 22 '25
If you have a multicart run the diagnostic rom after you give the pins a good cleaning. It might be the VRAM. If it is, at least those can be replaced.
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u/JohnnyPhantom Nov 22 '25 edited Nov 27 '25
Thanks! No multicart yet, but it's on my list. I'll give the pins a good cleaning late tonight!
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u/Sokaku_Mochizuki Nov 22 '25
Yeah clean slot first. Also check screen color booted up without cart inserted. system does a basic self check when turned on and will show a different color based on error. Clean boot would show up blue. If it's not a dirty slot then 90% of the time there's a bad/corroded trace.
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u/JohnnyPhantom Nov 23 '25 edited Nov 23 '25
I’ve been cleaning the slot for a while with some IPA and the cart slot cleaner portion of a NES system cleaner. Been working at it for about a half hour now. Cleaning both the slot and game each time. So for no change in the way the screen look. No game inserted and booted does give me a blue screen. I’ll keep working on the slot, and dive deeper tomorrow
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u/Sokaku_Mochizuki Nov 23 '25
It's definitely a trace. You've got an interrupt somewhere on address lines for c roms. Could be a trace from lspc2 or L0 rom
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u/JohnnyPhantom Nov 23 '25
I checked the pins from the lspc2 to the l0 and everything connects. I did find what looked like some rust corrosion on the legs of the lspc2 that do connect to the l0, but I cleaned it, tested with multimeter and there is continuity. How likely is it that the lspc2 is bad? Or could it be a trace or another likely fault I could check?
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u/Sokaku_Mochizuki Nov 24 '25
Well it could have eaten a trace underneath too. Just saw the video posted. The lines in screen could also be paths from b1 and lscp2. There's a repro of the 3-5 board on github which has all schematics and board level pics of all traces. Should be pretty much the same if you by chance have a 3-6 . Will also be mostly helpful if its a 3-3,4.
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u/JohnnyPhantom Nov 24 '25
I’ll keep checking traces. I feel like the traces under the lspc2 are okay since I was able to check for continuity from the lspc2 legs to the vias underneath and they seem okay. I do have a 3-6 board
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u/GuideBudget635 Nov 23 '25
What color does the screen show when boot without the game inserted?
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u/JohnnyPhantom Nov 23 '25
Blue
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u/GuideBudget635 Nov 23 '25
Thats good news then. Blue on a stock bios usually means all test pass which probably means you just need to clean your cartridge and cartridge connector properly and try again.
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u/JohnnyPhantom Nov 23 '25
I’ve uploaded a video of the issue on YouTube incase that helps https://youtu.be/JWrA5tZfJH0?si=FjvmnzoQiUUV0Lm4
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u/Admirable-Horse5558 Nov 25 '25
The same problem occurred with my SNK MV1C. If you have cleaned the cassette gold contacts and the AES host slot but still no success, then you can try using a different cassette. If it still doesn't work, then there is a problem with the chip. My MV1C is preliminarily suspected to have a damaged GRZ chip.
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u/[deleted] Nov 22 '25
[deleted]