Neo Geo:General Troubleshooting

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Testing Video

Turn on the Neo Geo with all game(s) removed. After a few seconds, it should boot to a blue grid. If you are able to see the grid, your video output is okay.

Testing Hardware

Flip DIP 1 to ON to enable test mode. See the Neo Geo:Test Mode page for more details.

Common Symptoms

Garbled Graphics

Garbled graphics or sound issues can be caused by:

  • The cartridge being inserted upside down. Ensure that the arrow on the cartridge is oriented closest to arrow on the motherboard/shell.
  • Dirty pins on the cartridge or connector. See the Cartridge Cleaning page.
  • The cart being too tight and not inserted all the way. This might happen if the cartridge and/or Neo Geo shell was painted, adding extra thickness.
  • The motherboard being flexed by inserting a cartridge too hard, resulting in cracked traces near the cartridge interface.
  • Needing to reflow the NEO-GRZ chip.

Freezing on Green Screen

Freezing on the green screen generally indicates a calendar error. Look for a leaking battery on the motherboard corroding nearby traces. Check the clock crystal next to the D4990 chip and try reflowing the pins and the capacitors near it.