(Topic ID: 273041)

System 7 Boot up theory of operation.

By arcadeforever

2 years ago



Topic Stats

  • 5 posts
  • 3 Pinsiders participating
  • Latest reply 2 years ago by zacaj
  • Topic is favorited by 2 Pinsiders

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    #1 2 years ago

    Hi all I am troubleshooting a system 7 game where when you turn it on, the game number comes up in the display 1 which I know usually means a dead/missing battery, but when I open the coin door to power it off and back on a few times quickly to get past that, it wont go past it and never puts the game into attract mode. Any ideas as to what could be wrong?

    Has anyone written a theory of operation for the bootup sequence? I was not able to find it.

    thanks!

    #2 2 years ago

    It does a very simple ram test on one byte that it uses to initialize PIAs - if this fails it goes to diagnostic test
    It initializes all the PIAs
    It initializes non-nvram
    It takes a checksum byte in the rom and compares it to a CMOS (nvram) byte - if this fails it goes to diagnostic test
    It checks dip switches and if set a certain way, goes to diagnostic test

    Instead of powering on and off, since it's system 7, it will exit at the end of audits. Just scroll through them all and exit. If it goes back into diagnostics, likely your nvram is bad, or your memory protect circuit from the coin door is bad. (most likely the 5101, though.... they're really static sensitive.)

    #3 2 years ago
    Quoted from slochar:

    It does a very simple ram test on one byte that it uses to initialize PIAs - if this fails it goes to diagnostic test
    It initializes all the PIAs
    It initializes non-nvram
    It takes a checksum byte in the rom and compares it to a CMOS (nvram) byte - if this fails it goes to diagnostic test
    It checks dip switches and if set a certain way, goes to diagnostic test
    Instead of powering on and off, since it's system 7, it will exit at the end of audits. Just scroll through them all and exit. If it goes back into diagnostics, likely your nvram is bad, or your memory protect circuit from the coin door is bad. (most likely the 5101, though.... they're really static sensitive.)

    Thank you, Its not going into attract mode, would the coin door switches work still?

    #4 2 years ago

    No, if you don't get attract mode, coin switches won't do anything.

    #5 2 years ago
    Quoted from slochar:

    No, if you don't get attract mode, coin switches won't do anything.

    The diagnostic switches will though, if that's what you mean

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