(Topic ID: 241036)

Tech: MM - DMD Issues??

By PinPlayer2

2 years ago


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  • 14 posts
  • 6 Pinsiders participating
  • Latest reply 2 years ago by PinPlayer2
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    #1 2 years ago

    Hi All, On my Willams MM - Original, I turned it on and noticed that the DMD was wavering and all the middle was out and around the edges was wavering an lit. The more I have had it on troubleshooting it, Now the DMD is totally out.

    Game has worked flawlessly for 11-12 years I've owned it.

    Here is what I've checked:
    1) I put in a spare DMD that is used but worked last time I used it but had one or two dots weak. Nothing it is totally dark
    2) All 6 LED Power Driver Voltages LED's are lit signifying I have all my voltages
    3) LED 501 is flashing at it normal rate for the +5VDC
    4) All 3 CPU LED's are working as manual indicates they should
    5) I tested AV Board J605, pin 1 & 2 and I am getting 87.6 VAC
    6) At J604, with the DMD connector unplugged, here are my readings:
    Pin 1 = -1.7 VDC
    Pin 2 = -1.3 VDC
    Pin 6 = 0 VDC
    Pin 7 = 0 VDC
    Pin 8 = 0 VDC

    At the DMD with connector connected:
    Pin 1 = -1.7 VDC
    Pin 2 = -1.3 VDC
    Pin 6 = 0.08 VDC
    Pin 7 = 0.1 VDC
    Pin 8 = 0.1 VDC

    What is my problem, anything else I need to check?
    Trying to figure out where my problem is.

    Thanks for any help!

    #2 2 years ago

    Also the whole game plays normally and all other functions are normal

    #3 2 years ago

    Check the fuses on the AV board.

    #4 2 years ago

    Listen to DumbAss, good advice. May have to change name to SmartAss.

    #5 2 years ago
    Quoted from DumbAss:

    Check the fuses on the AV board.

    Don’t just check, replace it. I have had fuses that check ok but do that on DMD’s. Not fully blown. Replace and it maybe fixed. Then I would swap DMD’s with another machine that you know works. (Put the mm dmd in another machine) Then swap the ribbon cables. If not that then swap the AV Board with another WPC95 game if you have one (SS and CV in your profile). Put the MM AV board in the machine that works so if you have voltage issues in mm won’t damage good board. If board does not work in other machine that is your issue. You will find what your issue is if you go through that. The WPC95 AV board you can buy from rotten dog as they just got them again. Last year impossible to find. Have someone fix your original AV board as the WB originals have a premium. Then use the rottendog as your spare board once you get the original back. Having a spare is key for WPC 95 games. I believe you a have bad a AV board but most expensive fix. Let us know! FYI color DMD’s take stress off of that board as they use 12v power supply instead of high voltage. Let someone with experience fix that board. Some great guys that specialize on them on pinside.

    #6 2 years ago
    Quoted from PinPlayer2:

    6) At J604, with the DMD connector unplugged, here are my readings:
    Pin 1 = -1.7 VDC
    Pin 2 = -1.3 VDC
    Pin 6 = 0 VDC
    Pin 7 = 0 VDC
    Pin 8 = 0 VDC
    At the DMD with connector connected:
    Pin 1 = -1.7 VDC
    Pin 2 = -1.3 VDC
    Pin 6 = 0.08 VDC
    Pin 7 = 0.1 VDC
    Pin 8 = 0.1 VDC
    What is my problem, anything else I need to check?
    Trying to figure out where my problem is.
    Thanks for any help!

    http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Testing_DMD_Controller_Power

    Pin 1 = -112V
    Pin 2 = -100V
    Pin 6 = +5V
    Pin 7 = +12V
    Pin 8 = +62V

    If you're not getting +5V then I'd question your measuring method. It might be that you're measuring AC voltage instead of DC voltage and possibly using an incorrect reference point. If you are measuring AC voltage then because the output is DC I would expect to see numbers in the range that you provided.

    Please read the quoted Pinwiki page. All the Pinwiki pages have extremely valuable information.

    I would still check the fuses. Please check them out-of-circuit (pull one end out of the fuse holder). You only need to check F601 and F602 as those are the high voltage display fuses.

    #7 2 years ago

    Thanks DumbAss, yes i had checked those two fuses in circuit but i wll definitely check them out of circuit.

    On the voltages, I clearly checked them in DC Voltage, the only AC check I did was on pin 1 & 2 of J605. I thought that was weird to as the LED on AV Board that flashes slowly signifies the +5VDC

    I'll check tonight and report back.

    Thanks for the help, greatly appreciated.

    #8 2 years ago

    Also the answer your question, I had the black lead clamped onto the ground strap on the bottom left of corner inside backbox beside the grounding screw/lug and then used only the red lead of Voltmeter. I am using a premium meter as I have a Fluke 87

    #9 2 years ago

    Hi Guys, I want this fixed ASAP, I ran home and rechecked this again, here are my findings:

    I removed all fuses on the AV Board and all checked good

    I did a recheck and secured a better ground and got more accurate readings:

    I tested AV Board at J605, pin 1 & 2 and I am getting 86.1 VAC

    At J604, with the DMD connector unplugged, here are my readings:
    Pin 1 = -116 VDC
    Pin 2 = -91 VDC
    Pin 6 = 5.03 VDC
    Pin 7 = 11.66 VDC
    Pin 8 = 2.2 VDC

    At J604, with the DMD connector plugged connected to DMD, here are my readings:
    Pin 1 = -116 VDC
    Pin 2 = -104.9 VDC
    Pin 6 = 5.03 VDC
    Pin 7 = 11.66 VDC
    Pin 8 = .63 VDC

    At the DMD with connector connected:
    Pin 1 = -117 VDC
    Pin 2 = -105 VDC
    Pin 6 = 5.0 VDC
    Pin 7 = 11.66 VDC
    Pin 8 = 0.6 VDC

    Next Steps?

    #10 2 years ago

    You have no 62V , if it's not a fuse you will likely need to rebuild your high voltage section.

    https://www.greatplainselectronics.com/proddetail.asp?prod=WPC95-HVP-KIT

    #11 2 years ago
    Quoted from Mageek:

    You have no 62V , if it's not a fuse you will likely need to rebuild your high voltage section.
    https://www.greatplainselectronics.com/proddetail.asp?prod=WPC95-HVP-KIT

    Thanks, yeah from what I reading that's what I am thinking too!

    #12 2 years ago
    Quoted from PinPlayer2:

    Thanks, yeah from what I reading that's what I am thinking too!

    Add some 220uF capacitors to the HV rebuild kit. However I thought those kits have been out of stock for years. Most likely you should go through that whole board thoroughly on the bench. The Audio side usually is not too far behind. You could plug in a color DMD and they usually work fine with the high voltage gone. Did you try another AV board in the machine?

    If you aren’t excellent at fixing boards let Rob Anthony or Chris Hibler do it. Both are great pinsider’s and experts on WPC95 AV boards.

    Rob Anthony
    Pinball Classics
    http://LockWhenLit.com
    Quality Board Work - In Home Service
    borygard at gmail dot com

    Or

    Chris Hibler - CARGPB #31
    http://ChrisHiblerPinball.com/contact
    http://www.PinWiki.com - The Place to go for Pinball Repair Info

    https://pinside.com/pinball/community/pinsiders/chrishibler
    https://pinside.com/pinball/community/pinsiders/borygard

    #13 2 years ago
    Quoted from Onwallst:

    However I thought those kits have been out of stock for years.

    They are usually out of stock, but every once in a while they're in stock for a week or so before he sells out. Interestingly, he lists all the parts in his kit on his website and he usually has all the individual components in stock. So, you could just order the parts and make your own kit. Yes, it would probably cost you $7 to do it that way, which is what I thought of doing myself.

    #14 2 years ago

    Hi guys, thanks all you prompt for the feedback. I am getting someone who knows board work well to go through it all.

    FYI..... I did try a known good DMD in the game and nothing, dead, it's the board for sure.

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