DM800 gets stuck in the boot screen

Discussion in 'DM800HD Hardware troubles and Repair support.' started by Kartino, Jan 2, 2021.

  1. Kartino

    Kartino New Member

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    My decoder struggles to start, very often it does not start and remains stationary on the DREAM MULTIMEDIA home screen.
    Removing and reconnecting power for many times manages to start and from that moment on it works correctly.

    I tried with another 12V 5A external power supply but the defect does not change, I replaced the 4 4700uf capacitors but even these did not improve the problem.

    when it is off for many hours it starts more easily, but if I switch it off and on again quickly it remains blocked.

    Has this happened to anyone? What could it be?

    20210102_231142_01.jpg
     
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  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Difficult defect because it can be due to a bad soldering, malfunctioning dc / dc chip, tuner and or worse, bad / outdated soldering of the CPU.

    But to start some things you can try ...
    Test it without a tuner, see if the problem does not occur.
    Try it as a test with a fan, blowing to the cpu and if not helping, blowing to a voltage regulator etc.

    In any case, based on your story, it seems to be related to warming up.
     
  3. Kartino

    Kartino New Member

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    Thanks Johnny,
    I have already tried to start without the tuner, it seems to be better but the problem is always present ...
    I try to resolder some dc /dc ic?
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    I would first do the fan test, using a small one blowing to a dc/dc area to see if it makes some difference.
    When it seems, then I would examine it deeper.
     
  5. Kartino

    Kartino New Member

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    I did some tests using the ice spry.
    I didn't understand much because trying to cool a few chips at a time it seemed to improve but insisting I saw that the problem remained.
    The component that seems to have given the best answers to the cold is the 54khz quartz, do you think this could be the cause of the problem?
     
    Last edited: Jan 6, 2021
  6. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    That's quite possible it can cause this problem if it has problems.
     
  7. toysoft

    toysoft Well-Known Member Staff Member

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    I have seen this on various clones, and there is some generations that do this... so perhaps a problem in the design, or perhaps a bad component (as the Oscillator/Quartz ?). I thought it was more due to the discharge of the caps, that needed to be completely flat to then be able to start again.

    TS
     
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