I have a NES, it is working normally, but one of the game colors appears as black. In the game Mario Bros 3, the name is in black, some blocks are black and the goombas too. What can it be?

  • 5
    I voted to reopen the question here because NES is on-topic here Oct 28, 2022 at 11:01
  • 4
    I think a picture would help, though. Nov 4, 2022 at 16:57

1 Answer 1


Because the NES cartridge port uses a separate bus for fetching graphics data versus CPU code, dirty cartridge connectors can often cause graphical anomalies without otherwise affecting cartridge behavior. If the lowest-order address pin to the cartridge was dirty, that might could cause some colors to appear incorrectly for some shapes. If the cartridge saw the pin as always seen as reading low signal, colors 1 would become color 3 and color 0 would become transparent. If it always read high, the roles would be swapped. If it's dirty, however, then it might usually read correctly except when the state of nearby pins is the opposite of the correct "address 0" state.

  • If @supercat's answer is the real issue, then operate as follows: don't blow it, open the cartridge with the appropiate tools and dissassemble it; then use a pencil erase gently on the contacts until they are bright. Reassemble the cartridge. If if does not solve the issue, then it is the ZIF connector and you may have to first clean it and if it still not works replace it with a spare.
    – Borg Drone
    Dec 7, 2022 at 10:01

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