DM800hd clone and "Dream Multimedia booting..." bootloop

Discussion in 'DM800HD Hardware troubles and Repair support.' started by DS-1, Sep 17, 2018.

  1. DS-1

    DS-1 Member

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    Hi guys! I have this old DM800hd clone that was working good until I turned it off for a couple of days. Now at the reboot it starts until the image screen shows up on the television. Then the bar on the OLED goes until the and and then it reboots with the bar at the start. "Dream Multimedia booting..." is showing on the OLED together with the bar.

    What should I check for it? It is not the first time it happens to me. To fix it, I just reaflashed the box. But it's pretty annoying to reflash everything after a couple of "pause" days.

    Thanks in advance for the reply!
     
  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    I'm thinking of the four 4700uf/10v caps replacement, or psu to weak.
     
  3. DS-1

    DS-1 Member

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    Thanks for the reply. Is there any way to check the caps without desoldering it?

    Also: can you give me a trick to check the PSU? Obviously now I've reflashed the box and it works...mah!
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    One cap is for the 3.3v, other three are for the 1.2v.
    But basically, if they do not visually display a defect, such as being swollen at the top, then they can only be tested after removal.
    Other option is to measure the two voltages while the receiver is active, and with channel switching, Hd/Sd.
    If the voltages stay stable, then there is no reason to think of a cap issue.

    Psu, when measuring the amps between the receiver and the psu it is possible to see if it's a psu issue but it is easier to try it with another psu, preferably a 12vDc 3 to 5 Ampere.
    But pay attention to the polarization, the center pin must be the plus side.
     
  5. DS-1

    DS-1 Member

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    Unfortunately I only have 12v 2A. The one I'm using with DM800hd is the only 3A I have at home. I've tried with a 2A and the result was the same.

    The strange fact is that now that I've flashed it again, it is working without problems. Also, I'm sure that it will works fine until I leave it turned off for a couple of days! So don't you think it could be a flash issue?
     
  6. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Sure, it could be the nand flash chip, however dreamup has a recovery bad sectors option which should shown bad sectors if they are there.
     
  7. DS-1

    DS-1 Member

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    I've checked that function before flashing the new image (i've done it via rs232...soooo slow!). It told me that the function was on, but nothing was done to fix it, so maybe it hasn't bad sectors.

    According to you, how is it possible that now the dm works and instead it stops working after a couple of days? The strange fact is that it will revive reflashing it, using the same psu!
     
  8. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    If the box just run, every day without issues, but failed after it was switched off a couple of days then it could be a cap issue, or the cpu failed when it's cold, then it could be a cpu issue, outdated solder.
    However the same results may also happen trough other caused as bad solder somewhere.

    If it happens after a x time of use, then it could be a issue with the flash chip, after all while using it writes statistics, channel info etc to the chip.
    Nevertheless, these are just thoughts about it, it could also caused due other, unknown causes.

    Best way (i think) is to monitor the behavior of the receiver with a rs232 terminal program, or check with it why it stops working when it fails.
     
  9. DS-1

    DS-1 Member

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    Now the issue is back after a couple of hours of inactivity. I'll try to check the caps first.