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Thread: MV1B - Dip Switches do not work?

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  1. #1
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    MV1B - Dip Switches do not work?

    I have a MV1B that had backup ram errors.

    Replaced the backup ram, and battery and the thing is working fine.

    EXCEPT...

    The DIP switches don't seem to work. I cant enter test mode, and dip-7 (free play) is set to ON, even if I turn it off.

    I checked with a multimeter - switching them does change the resistance between the two points on the underside of the board, so I don't think the switches themselves are faulty - it seems like something else.

    Any suggestions?

  2. #2
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    The only thing I can suggest is to measure the voltage or probe them to see if perhaps a pullup has failed or something. Beyond that I would trace it on the board - follow where its connection goes to, and the first chip you hit along the way is possibly the culprit. It could be trace damage somewhere perhaps - I would expect one end of the DIP switch to be connected to either 5v or ground (not sure which as I've never looked - suspected ground). So you could check that too.
    My YouTube channel contains some MVS repairs and stuff:-
    http://www.youtube.com/user/GadgetUK164

  3. #3
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    Check pin 15 to 22 of NEO-F0, this is where the dip switches goes.
    The pin is active low, e.g. it's tied to ground if switch is on.

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    The 1B doesn't have a Neo-F0 I think. It's a small board though should be easy to trace the connections.
    My YouTube channel contains some MVS repairs and stuff:-
    http://www.youtube.com/user/GadgetUK164

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    You are right, there is NEO-DCR and NEO-BUF instead:
    NEO-DCR on neogeodev wiki

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    Quote Originally Posted by nono2lozere View Post
    You are right, there is NEO-DCR and NEO-BUF instead:
    NEO-DCR on neogeodev wiki
    Nice work =D
    My YouTube channel contains some MVS repairs and stuff:-
    http://www.youtube.com/user/GadgetUK164

  7. #7
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    Quote Originally Posted by GadgetUK View Post
    The only thing I can suggest is to measure the voltage or probe them to see if perhaps a pullup has failed or something. Beyond that I would trace it on the board - follow where its connection goes to, and the first chip you hit along the way is possibly the culprit. It could be trace damage somewhere perhaps - I would expect one end of the DIP switch to be connected to either 5v or ground (not sure which as I've never looked - suspected ground). So you could check that too.
    Thanks for the replies everyone!

    They (switches) do test continuity to ground when switched on. Dip Sw 7 does not test grounded when the switch is not on, so my guess is that the switches are physically okay, because it seems to behave like the rest in continuity tests.

    I tested the other dipswitches when I do not have a cart inserted, and 2-6, and 8 register on or off properly. 7 is always on in test, and otherwise. Not really a problem as I don't intend on routing a game etc.

    I don't have a logic probe, and looking at the traces seems impossible. I can't tell looking at the board where they go.

    But Looking to the pinouts, is that show Pin 79 is where dip switch 1 goes?

    Also - would there be a way to do hard/software setups with a Universe bios? (i dont own any)

    That might be a quick and fairly cheap way to go.

  8. #8
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    - Issue resolved with Unibios workaround -

    Installed Biosmasta and Universal Bios and use that instead to change slot / cart settings.

    Works way better now with my 161/1 - can change the individual game settings which I did not know it would do!

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