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Original question:

Horizontal line on DMD

DLP7000: Horizontal Line across display

Briana Chen
Prodigy 10 points
Part Number: DLP7000

When I first power on the DMD (DLP 7000) with the on switch, I see a horizontal line across the display, even as it cycles through test patterns without connection to a computer. I am using the DLP Discovery 4100 kit and I've switched boards and flex cables with known working ones, which have not changed anything. Loading images/resetting/clearing and pressing the hardware reset (SW2) has also not removed this line. Additionally, pressing SW3 (manually float the mirrors) does remove the line so the mirrors themselves seem to be working correctly. 

It previously did not do this so I'm not sure what connections, if any, to test and what other ways I can troubleshoot.

Thanks!

  • 0
    TI__Mastermind 27605 points

    Hi Briana,

    Perhaps it is an issue with the connectors for the data themselves. I'll have someone familiar with this board follow up

  • 0 in reply to made4engineering
    TI__Guru 54285 points

    Hello Briana,

    A picture of the artifact would be very helpful to diagnose the issue.

    Fizix

  • 0 in reply to Fizix
    Prodigy 10 points

    Hi, here's what the DMD looks like.

  • +1 in reply to Briana Chen
    TI__Guru 54285 points

    Hello again Briana,

    Thank you for the picture.  This is what I suspected.  This band is an "MBRST" group that is not connected completely.

    I also notice that two of the bolts are missing that holds the DMD to the mechanical interface.  I would first complete the mounting with all four bolts and test again.

    If that does not fix the issue, I would carefully take apart the mounting hardware that holds the DMD to the DMD PCB.  Inspect the interposer for any missing "C" springs (in the little holes in the interposer).  Or see if any have gotten turned sideways in their slot.

    For missing "C" springs, simply hold the interposer up against a light background and you will easily see extra light through a hole if it is missing.  

    For turned "C" springs you will need a stereoscope or a low power microscope (10X - 20X) is more than enough.

    If either one is true you will need to obtain a new interposer before proceeding.  If not then carefully clean the pads on the back of the DMD and on the DMD PCB with IsoPropyl Alcohol (IPA) and carefully reassemble and test.

    If that does not fix the issue, then one end at a time carefully remove the flex cable and clean the pads and check the cable connector for any "debris" in the pins.  After each end test the system.

    I hope this helps.

    Fizix

  • 0 in reply to Fizix
    Prodigy 10 points

    Unscrewing and rescrewing things did help, thank you so much!

  • 0 in reply to Briana Chen
    TI__Guru 54285 points

    Thank you for letting us know.