Tech: Page Mr. Do! Tech expert

Archived from groups: rec.games.video.arcade.collecting (More info?)

I've got this Mr Do pcb that belongs to Keith C. in NJ. The game boots
up. On the title screen there is no mr do. The sound works, you see
the color bars scroll inside the mr do title. Then a tunnel starts to
dig but the sprite of mr do is not shown. I've checked the voltages
right at the board and it's adjusted to 5v. I've run the self test and
it finds nothing.
When you coin up and start the game, there is no mr do sprite. The
music plays and as soon as it ends, the game acts as if you finished
the level and goes to the next.
Any help would be greatly appriciated as he was sold the board with a
jamma adapter as tested and working 100%.

Thanks,
Don
NJ
7 answers Last reply
More about tech page tech expert
  1. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Don,

    Funny you should mention that. Keith is a regular here and has already
    been posting about this problem.

    Hope he's not mad at you for sending you a board to get fixed, only to
    find you here asking the same things he was.

    Don't know what type of relationship you have to/with him. But If he
    sent you the board as a repair job, and finds you on his stomping
    grounds asking the same questions he was; I would be feeling kinda
    embarassed by now.

    "he was sold the board with a
    jamma adapter as tested and working 100%.
    "

    I think that might start something as it insinuates he was sold both
    items by the same person. In fact IIRC the board was a feepay buy and
    Mark Spaeth sold him the adapter.

    Pull the schematics and start diggin through the sprite systems.

    - Matt
  2. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Sounds to me like a sprite ROM access problem. Can you see the bad
    characters? (Monsters or whatever the heck they are)
    I'm speaking from the hip here but if this board is anything like other
    classics, there are 2 sets of graphic ROM(s): 1 for sprites and one for
    tiles.
    Looks like the tile ROMS are being accessed fine since you can see the
    title screen etc. And the fact that you pass self test leads me to
    believe that it's not a VRAM addressing issue.

    -Adam
    =================
    www.onecircuit.com
    =================
  3. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Thanks for looking out for me Matt. Actually Don's local and we've been
    swapping and buying stuff back and forth for a while so it's cool.

    I did get the board on ebay and I have to tell you.. I can't imagine that a
    problem like what we're seeing with this board all of a sudden happened in
    shipping. Don mentioned some people plug a board in.. they see a title
    screen and bam.. it's a "working board". So i guess that's why the ebay
    seller won't do anything for me. "It was working when we tested it." To say
    nothing of what that 'testing' consisted of.

    I'm thinking that is the case with this board. Could this be a ROM issue? I
    ask because I understand there's glass bubbles on the rom chips because you
    erase them with some UV light. About 2 rom chips on this board had the glass
    bubbles exposed (others had stickers on them). Is it possible for some code
    to be partially erased even though the self test shows all is normal?

    Also.. I mentioned there were some sound issues originally.. it turns out
    that there is something up with the adapter I got from mark.. when i was
    adjusting volume today my finger bumped the cap on the adapter and i got
    considerable static.. gently tapping the top of the cap and then moviing a
    little with light pressure caused more static and at some points stopped it
    completely.

    I'm thinking since it was shipped in a flat envelope.. maybe the cap got
    mashed on a little in transit? We're going to de and re solder the cap which
    should fix the adapter problem..

    (note to mark.. maybe ship those things in a little box or something to
    avoid this prob for other people. i'll take the hit on this one and fix it
    myself so i don't have to send it back and forth to you.)

    again.. if anyone has any ideas.. maybe even a spare set of mr do chips we
    can try to swap, i'd appreciate it.

    thanks.
    k.


    "Matty-t" <matthews@audio-doctors.com> wrote in message
    news:1119128833.844608.262910@g44g2000cwa.googlegroups.com...
    >
    > Don,
    >
    > Funny you should mention that. Keith is a regular here and has already
    > been posting about this problem.
    >
    > Hope he's not mad at you for sending you a board to get fixed, only to
    > find you here asking the same things he was.
    >
    > Don't know what type of relationship you have to/with him. But If he
    > sent you the board as a repair job, and finds you on his stomping
    > grounds asking the same questions he was; I would be feeling kinda
    > embarassed by now.
    >
    > "he was sold the board with a
    > jamma adapter as tested and working 100%.
    > "
    >
    > I think that might start something as it insinuates he was sold both
    > items by the same person. In fact IIRC the board was a feepay buy and
    > Mark Spaeth sold him the adapter.
    >
    > Pull the schematics and start diggin through the sprite systems.
    >
    > - Matt
    >
  4. Archived from groups: rec.games.video.arcade.collecting (More info?)

    I don't charge Keith for repairs or anything. We just kinda help each
    other out. He told me that someone said the problem may be voltage or
    something stupid so I told him to drop it by. Most of the time problems
    I've found are not the basic voltage or reseating problems that are the
    usual answere to a problem though they are a good place to start. I'm
    thinking theres probably a couple of problems with this board. The
    first being sprite processing problems. The second being in the game
    logic to process the status of the game. I usually don't get to far
    into trouble shooting but if someone gives me specific ideas on certain
    chips to change then I usually try that.

    Thanks,
    Don
    NJ

    --
    Sent via Gamer Newsgroups
    http://www.gamernewsgroups.com
  5. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Have you done the self test yet?? Mr Do will run with corrupted or missing
    roms. I had a problem like this and it turned out to be a bad rom socket.
    Anyway, hold the player one and player two buttons down when you turn it on.
    It should do a self test. Might show up a rom problem.


    "ajcrm125" <ajcrm125@gmail.com> wrote in message
    news:1119136878.102151.117570@o13g2000cwo.googlegroups.com...
    > Sounds to me like a sprite ROM access problem. Can you see the bad
    > characters? (Monsters or whatever the heck they are)
    > I'm speaking from the hip here but if this board is anything like other
    > classics, there are 2 sets of graphic ROM(s): 1 for sprites and one for
    > tiles.
    > Looks like the tile ROMS are being accessed fine since you can see the
    > title screen etc. And the fact that you pass self test leads me to
    > believe that it's not a VRAM addressing issue.
    >
    > -Adam
    > =================
    > www.onecircuit.com
    > =================
    >
  6. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Yeah. I believe Don said he ran this and everything came up good.
    Since I have no idea how this board was stored.. for all I know it could
    have been on a shelf under a window that got a few hours of sunlight a day.

    If the problem turns out to be a code issue and not a physical damage issue
    I think I'd have a bit of a cause against the ebay seller who listed the
    board as 100% working.. unless anyone thinks a code issue could be caused by
    shipping. If they listed it as "working" then yeah... they may be able to
    say.. 'it booted up.. so it was working'. 100% working though means no
    problems at all and an "all sales final" note in the description shouldn't
    absolve them of misrepresenting an item.

    k.


    "VaxX" <geoff_gunn@hotmail.com> wrote in message
    news:42b55029$0$257$61c65585@uq-127creek-reader-03.brisbane.pipenetworks.com
    ..au...
    > Have you done the self test yet?? Mr Do will run with corrupted or missing
    > roms. I had a problem like this and it turned out to be a bad rom socket.
    > Anyway, hold the player one and player two buttons down when you turn it
    on.
    > It should do a self test. Might show up a rom problem.
    >
    >
    >
    > "ajcrm125" <ajcrm125@gmail.com> wrote in message
    > news:1119136878.102151.117570@o13g2000cwo.googlegroups.com...
    > > Sounds to me like a sprite ROM access problem. Can you see the bad
    > > characters? (Monsters or whatever the heck they are)
    > > I'm speaking from the hip here but if this board is anything like other
    > > classics, there are 2 sets of graphic ROM(s): 1 for sprites and one for
    > > tiles.
    > > Looks like the tile ROMS are being accessed fine since you can see the
    > > title screen etc. And the fact that you pass self test leads me to
    > > believe that it's not a VRAM addressing issue.
    > >
    > > -Adam
    > > =================
    > > www.onecircuit.com
    > > =================
    > >
    >
    >
  7. Archived from groups: rec.games.video.arcade.collecting (More info?)

    Keith in NJ <winner@soulshot.com> wrote:
    : Yeah. I believe Don said he ran this and everything came up good.
    : Since I have no idea how this board was stored.. for all I know it could
    : have been on a shelf under a window that got a few hours of sunlight a day.
    :
    : If the problem turns out to be a code issue and not a physical damage issue
    : I think I'd have a bit of a cause against the ebay seller who listed the
    : board as 100% working.. unless anyone thinks a code issue could be caused by
    : shipping. If they listed it as "working" then yeah... they may be able to
    : say.. 'it booted up.. so it was working'. 100% working though means no
    : problems at all and an "all sales final" note in the description shouldn't
    : absolve them of misrepresenting an item.

    There's a mux right in front of the color proms that selects sprite or
    background data... I bet you'll find it's always selecting background :)

    --
    Mark Spaeth mspaeth@mtl.mit.edu
    50 Vassar St., #38.265 mspaeth@mit.edu
    Cambridge, MA 02139
    (617) 452-2354 http://rgvac.978.org/~mspaeth
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