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Museum of the Game® & International Arcade Museum® Forums
I'm having an issue getting enough voltage to write high scores to the 2055 on a Centipede board. The best I can get is -26.7
The +/- 22s are measuring 23 and 24, and the +/- 15s are both measuring 15. The -30 test point was only measuring -8.
The 555 was totally dead. I socketed and replaced it and the voltage went up to -26.7
The 1uf cap at C86 tested good, and I replaced the 1N4001 diodes. No change.
In test mode, instead of the usual 4 FF I have a 4 20, and occasionally 4 AA or 4 5B.
Any thoughts?