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  • Wonderboy fault

    Have a graphic fault with a wonderboy in that no sprites show. Game plays correctly with proper background graphics etc.

    Any idea's where to start?

    Would love a schematic.
    Last edited by humpalot; 27th June 2009, 09:44 PM.
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    Another Holiday
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  • #2
    Would love a WonderBoy
    Wanted: Harlem Globetrotters Pinball

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    • #3
      is it bootleg or original? if bootleg id be looking at the big rider first and possibly ram.

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      • #4
        Originally posted by Arcade King View Post
        is it bootleg or original? if bootleg id be looking at the big rider first and possibly ram.
        it's an original. Do you suspect the custom there?
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        • #5
          are you handy with a probe? id be checking around those customs for starters and anything connected to them.
          think ive got a scrap Sega system "A" shinobi which I "think" used those customs that your welcome to.
          Look for any "F" chips also. Basically look for anything dead or stuck high or low.

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          • #6
            Thanks AK.

            I hate playing around with arcade PCB's.
            Last edited by humpalot; 27th June 2009, 09:43 PM.
            WANTED

            Another Holiday
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            • #7
              From my own Wonder Boy repair log:

              Symptom: All sprites are a thin vertical line, or not visible at all
              Cure: Bad outputs on the LS175 at location IC91, particularly pin 3

              Not saying it's that chip at fault on your board, but it will give you an idea of the area to look at; check the I/O on that IC anyway, then if that's okay work around the ICs feeding it signals and what processes those that it spits out.

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              • #8
                Customs are usually pretty hardy on Sega boards (except Sega system 18 ) I think everybody will agree a board worth saving.

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                • #9
                  Most definitely. A lot of people love Wonder Boy, more especially the original boards.

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                  • #10
                    I would instantly suspect the 74ls04 chip at location 1N, ie ic97.

                    Have seen that chip cause the exact same fault! Piggy back a known good 04 on top of it to test.
                    Sic transit gloria Atari!

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                    • #11
                      Originally posted by Womble View Post
                      I would instantly suspect the 74ls04 chip at location 1N, ie ic97.

                      Have seen that chip cause the exact same fault! Piggy back a known good 04 on top of it to test.
                      Thanks I'll look at that and LS175 at location IC91 before going onto and checking what AK suggested.

                      Just find arcade boards with no schematics too time consuming.

                      The thing only died yesterday one of my fav games. If I can sort it out I might look at the other 3 wonderboys I have in the pile (all bootlegs)
                      WANTED

                      Another Holiday
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                      • #12
                        As Womble suggested piggy backing is your friend even if your not good with repairing boards piggy backing a known good chip on top usually works.

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                        • #13
                          All RAM chips good, custom chips appear OK, the 2 74 series IC's mentioned also test good.
                          Last edited by humpalot; 23rd June 2009, 06:22 PM.
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                          Another Holiday
                          .

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                          • #14
                            Do you have a scope? Its going to be either a stuck pin on a TTL or a floating output. Continuity test to where the 4 outputs of the LS04 go, then check the outputs of those chips. Something somewhere has lost the plot, if the board is full of F chips then it can be easy to spot as the outputs just get disconnected, so its neither high or low.
                            Sic transit gloria Atari!

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                            • #15
                              No F chips on the board. I'll have another play with it tonight checking around the 04 chip.
                              WANTED

                              Another Holiday
                              .

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