(Topic ID: 291262)

DMD Black screen

By saddys

3 years ago



Topic Stats

  • 4 posts
  • 2 Pinsiders participating
  • Latest reply 3 years ago by saddys
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    #1 3 years ago

    Good morning, I have a problem with one dmd controller (Wpc 89).

    The screen on dmd is Black.

    In the past I have always bought kits at the various sites and they have always worked at the first shot.

    Then I decided to buy the individual components on aliexpress.

    I replaced all the components of the high voltage (mje, 2n,vary resistor, zener diode, etc) with components bought on aliexpress.

    Result: The screen is Black.

    The voltages, however, seem correct to me:

    The first time I turn on, I have these values
    -110v -98v 12v 4.95v 62v

    After a few minutes
    -114v -102v 12v 4.95v 66v

    If I connect a pin2dmd to the controller I see everything correctly.

    If I use another controller I see everything well on the dmd gas.

    So there's something about high voltage that I can't figure out the problem, because everything seems ok. Any advice?

    Can it be the poor quality of some component even if the values are correct?

    Thank you!

    #2 3 years ago

    Loaded or unloaded?

    Did you measure those voltages with display connected?

    #3 3 years ago

    With display connected!

    I have to measure without it too?

    #4 3 years ago

    So, new complete measure of faulty board:

    With dmd: -110v -98v 62v (measured offset 11.92v), after one minutes on, offset reached 12.02v
    Without dmd i have: -112v -90v 64v

    With another controller board that is ok on dmd, i have:

    With dmd: -118.2v -106.2v 67v (measured offset 12.04v)
    Without dmd: -120.4v -96.7v 67v

    With a third controller board that is ok on dmd, i have similar voltages of the first faulty board:

    With dmd: -111.3v -99.3v 65v (measured offset 12.01v)
    Without dmd: -112v -91.5v 66v

    The only "different" thing is the offset which is just below 12v (11.92v) at power on, but soon rises to 12v. If then I turn off and turn on quickly, the dmd will not turn on despite offsets of 12.02v.

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