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Rodgers 640 CPU part number information needed

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  • Rodgers 640 CPU part number information needed

    I’m helping repair a Rodgers 640 that would not power on. Replacing the CPU board fixed the problem. The part numbers are slightly different, and I was hoping someone might know what the difference is. The original CPU is ROC5042-302 and the replacement is ROC5042-303.
    The replacement board has eproms that came with it. They are number 4002-640-F1 and F2. The originals eproms are number 4002-640-C1 and C2. Everything seems to work, so we decided not to move any parts between CPU boards and use the F1, F2 eproms.
    I’m sure there is some mismatch, but the owner is happy it can be played again.
    We probably will not change any parts, but if anyone has an idea on the numbers, let me know.

  • #2
    The tech manual I have for the 640 shows 5042-303 as the CPU assembly number so I think you are good to go.


    • #3
      Thanks Toodles.
      Do you have any information on the eprom chip part numbers. Could the F1 and F2 numbers be for an organ with a different stop set?


      • #4
        I don't have EPROM part number history, you'd probably have to get that info from the factory. But the 640 in the part number indicates it is for the 640 organ; C vs F is probably a revision. Firmware get revised for any number of reasons. Early in the run of the 640 organ pipes were not an option, but in that era Rodgers came to make all models pipe compatible, so perhaps that is the revision reason; another reason is that Rodgers might have made MIDI an option for this model after the model's initial release, which would have necessitated a firmware revision.


        • #5
          Thank you toodles for the information. I agree, the numbers look like a revision update for a 640. Anyway, the organ works and an old board has a new life.