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(Topic ID: 242922)

Bally -35 MPU 5th Flash Issue

By crazi

4 years ago


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    #1 4 years ago
    OP
     
    DAD

    crazi

    Pinside member

    GB Coatbridge

    15y 41,400 307 8 6

    Hi All

    So Ive been repairing this MPU - done loads to get it working but now I have a strange issue.

    The board boots all 7 flashes on the bench. When in the machine it fails the 5th Flash. If I take of J1 it does 7 flashes. So I re-socketed U11 just in case but no change.

    The fact that if I remove J1 it flashes would normally tell me it's a "load" issue or bad connection but I have checked all the IC's linked to U11 5th Flash like U20, U19, U14 etc and cant find any issue.

    The fault is on the MPU as the machine works fine - this is a spare MPU board i'm repairing.

    Thoughts? What am I missing?

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    #3 4 years ago
    OP
     
    DAD

    crazi

    Pinside member

    GB Coatbridge

    15y 41,400 307 8 6

    C65 & C67 were not measuring right. Replaced them and now it boots up in to attract mode

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