Servicing a Game boy DMG (Original)

Discussion in 'Other Handhelds' started by Pokepicker, Jun 19, 2017.

  1. Pokepicker
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    Pokepicker GBAtemp Regular

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    Hello

    I recently acquired a fairly cheap Game boy DMG. It was in a worse shape then the images and description would lead one to believe.
    So I decided this device was in need of some tender loving.

    I opened the case, and removed the PCB so I could clean the outer shell itself. At the same time I washed the buttons, as well as fixed a bunch of dead vertical columns. Great success. The shell looks nicer, the buttons are less gross and the screen is back to it's old glory days.

    I still have two issues with this device.
    1: The battery connectors are dirty/damaged from what I would guess was a leaky battery.
    - Ordered new ones as cleaning them didn't really work out that well. I'm guessing the dirty connectors might be why the machine will not always turn on. If it is reluctant to turn on, wiggling the batteries a little make it work.
    Luckily I can't see any damage on the PCB itself.​

    2: The buttons are unresponsive.
    - I never tested the buttons before fixing the screen, but after assembling the Game boy after it's cleaning process, the buttons don't work.
    Someone recommended that I take some paper and rub on the black spots on the back of the rubber pads. I re-opened my DMG, loosened the PCB with the LCD on it from its case and rubbed the black spots on the rubber pads.
    Putting the PCB half way back in place (just a couple screws holding it), I started the Gameboy again to test. Now it seemed like it was pressing buttons "at random", or more likely it was highly sensitive. I figured that was a good sign. At least it was doing something when having its buttons pressed.

    After I assemble it again, the buttons are again completely dead. A/B, SELECT/START and possibly the D-pad (unknown since I cant press my way passed any Title screen and thereby be able to test the arrows).

    I have ordered a new set of rubber pads. I really hope this will work. But in the case it does not, what should I do? Someone also recommended that I clean the PCB in the area where the rubber pads would be making contact. What should I use to clean the PCB?​
     
  2. britain4

    britain4 GBAtemp Regular

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    I would use rubbing alcohol on a cotton bud to clean the connectors on the PCB, or alternatively a pencil eraser.

    Try the same thing on your rubber pads and you might find they will start working properly again. If not, the new set of pads should fix it. If it still doesn't work there may be damage to the board somewhere but I would say unlikely
     
  3. Pokepicker
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    Pokepicker GBAtemp Regular

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    Ok.

    I really hope the new rubber pads are going to help.
    Tore down the DMG again, cleaned both the button area of the PCB as well as the black pads on the rubbers.
    No improvement.

    I asked a similar question in some FB group where someone mentioned the CPU could be damaged if the ribbon connector is removed while the Gameboy is powered on.
    I'm going to hope this is not the case, as I haven't done it. And I'm doubtfull that the previous owner has had the case open and done any work.

    Now I have never seen a DMG with a damaged CPU, but I hope it is ok.
    I find it strange the buttons kinda worked while having the PCB loose in the case. But upon screwing the PCB in place the buttons quit responding.

    Is the CPU even replacable if that is the faulty part, or is the PCB more or less junk at that point?
     
  4. Todderbert

    Todderbert Korg Fanboy

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    I had one gameboy I was unable to bring back to life and it had corrosion on the top pcb too. It was battery leakage creep that went in and destroyed both boards. It sucks, I scraped the boards but saved the housing and buttons for a future build. I'm really into DMG collecting and bring them back to life is awesome.

    Yes you can change the CPU but you need skill. The coolest mod is changing it with the super gameboy cpu..yep it works and it boots up fast with no startup screen or beep. Cool for the chiptune musicians.

    [​IMG]
     
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  5. Pokepicker
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    Pokepicker GBAtemp Regular

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    The new rubber pads arrived.
    After installing them I see that the buttons are still non-responsive.

    I wonder what the problem could be. Again, they seemed to work once when I had the PCB laying loose from its case. But upon screwing it back together they quit working.

    Are there any contact points between the two PCB's that would be touching, but might not be?
     
  6. Todderbert

    Todderbert Korg Fanboy

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    Odd. You have counted 10 screws to mount the front PCB to the front half of the case and made sure they are in the proper spots. The only connection issue would be the ribbon cable from the top PCB to the CPU PCB. I'm leaning on there is a crack somewhere on the front PCB and it causes a disconnect of a certain trace or traces to the buttons. when not under screw tension you may get it to randomly work..its the only thing I can think of. If you had a donor top pcb you could try to swap it to check, and I'll bet it works fine.

    I own a few so I have some experience. I have backlit and biverted screens, and fixed the vertical line syndrome many a time.

    [​IMG]
     
    Last edited by Todderbert, Jul 5, 2017
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  7. Jayro

    Jayro MediCat USB and Mini Windows 10 Developer

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    I had no idea that was even possible, and that's cool as hell.

    Can it be done to the Gameboy Pocket as well?
     
  8. Todderbert

    Todderbert Korg Fanboy

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    The cpu changed to MGB so the voltage/audio pinouts are different, and I'm not sure but the chip size changed..have to check that. So this only works for the original Gameboy, because the SuperGameboy was really a DMG in a SNES cart.

    Could open one of mine to check.

    [​IMG]
     
    Last edited by Todderbert, Jul 5, 2017 - Reason: pic added
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  9. Pokepicker
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    Pokepicker GBAtemp Regular

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    @Todderbert I have all the screws, but I am quite sure they are not in the right order.
    It didn't even come to me mind that they might be different.

    Do you have a chart or something that would show me what screw goes where?
    This is a old DMG that uses a small Philips(?) head screwdriver instead of the proprietary triwing ones.