DMD needs a bit to warm up

Started 1 year ago by mickthepin in forum TechTech: Generic.


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DMD needs a bit to warm up


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  • Started 1 year ago by mickthepin
  • 7 Pinsiders participating in this thread.
  • Latest reply from jalpert

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    1 year, 10 months ago
    #

    If you have a DMD that warms up after a full game and becomes 100%, as appose to having a 1 or 2 dots out to start with. What is this caused by, I hear people refer to this as gassed out? Is this right? Is there anything I can do to fix this or make it a bit quicker to warm up after first being turned on?


    1 year, 10 months ago
    #

    Probably outgassing, or weakened high voltage components.


    Atomicboy

    Pinball guru
    5,470,250 2
    1 year, 10 months ago
    #

    It's gassed. This stresses the PS as well. You need to bite the bullet and replace.


    1 year, 10 months ago
    #

    But what does the gassed out or out gassed exactly refer too. Is it that some neon gass escapes the bulb and it doesn’t fire right off the bat anymore?


    1 year, 10 months ago
    #

    Some of my games also have it.
    Havent investigated the problem but I think its more the capacitors on the driver board getting olf than the dmd.

    Yes outgassing is that. A dmd is two glass pieces in vacuum with gas in. When the dmd gets older the airtight seal breaks and gas starts to Escape. More current is needed to display things.
    Usually the dmd isnt totally bright but has some clouded parts.


    Atomicboy

    Pinball guru
    5,470,250 2
    1 year, 10 months ago
    #

    Once it starts to go, the glass is done and you need to replace. Again, leave it too long and you may have to replace the PS as well, although I have seen people leave them gassed partially forever with no other issues.


    1 year, 10 months ago
    #

    Easy way to check is power up game and check voltages at the big connector, if they are good you need a new DMD, if they are off, you need to rebuild the high power section of your DMD driver board.

    LTG


    1 year, 9 months ago
    #

    Thanks guys. Sorry to bring this post up again but after some investigation it’s only the horizontal single lines in the test that are affected. The rest of the test is perfect. If it is the high power section, where is that located?


    1 year, 9 months ago
    #

    My BSD DMD works fine but can be totally blank when pin switched on and then I wait and wait, and then all ok. So reading this, maybe I need to replace DMD even though no missing lines etc?


    1 year, 9 months ago
    #

    Yep I hear the replacement idea. I just wondered why all the tests are fine except for the horizontal single lines.


    Atomicboy

    Pinball guru
    5,470,250 2
    1 year, 9 months ago
    #

    I know there are greater power demands placed on the PS when the dmd starts gassing. As such, maybe when testing the verticals, there is enough power to provide more for this, but you again notice the issues when the horizontals are going.

    Either way, you have other DMDs in your other machines, you can swap one in to see that it works fine, but otherwise, there isn't much else to discuss with DMDs. Once they go, there is usually next to nothing you can repair, and it's just one of those things you have to buy.


    1 year, 9 months ago
    #

    Pull the DMD from another DMD game. If the screen turns on right away, your DMD is wonky.

    If your DMD is wonky, it's probably best to replace it.

    Shapeshifter said:

    My BSD DMD works fine but can be totally blank when pin switched on and then I wait and wait, and then all ok. So reading this, maybe I need to replace DMD even though no missing lines etc?



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