Doesn't boot

Discussion in 'VuPlus Duo2 Hardware troubles and Repair support' started by amila4341, Feb 15, 2021.

  1. amila4341

    amila4341 New Member

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    My duo2 does not boot. It hangs as following image. when I start after long time it boots.when switch off and then switch on again it hangs.
    Voltage measurement are following
    20210215_154342.jpg 20210215_155135.jpg
     
    Last edited: Mar 31, 2021
  2. Aliraza63

    Aliraza63 Active Member

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    Which image you have installed ?
    Did u check it to install fresh image ?
     
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  3. amila4341

    amila4341 New Member

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    open blackhole 4.4
    Yes no change.
    If I switch on after around 24 hours it boots.when I switch off and try to switch on by rocker switch it hangs there
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    ... Voltage measurement are flooowing ...
    By reading this then I think it may be a unstable psu.
    Check the 12vDc from it, see if it's stable to 12v and not under the 12v.
     
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  5. amila4341

    amila4341 New Member

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    It is under 12v .it's around 11.82v
     
  6. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    That could mean ...

    Or the motherboard consumes too much, causing the 12v to collapse.
    Or the 12v power supply has been weakened, usually due to outdated capacitors.

    I think...
    Test the motherboard with an external 12vDc adapter instead of using the internal one, which should be at least 3 amps.
    Make sure to connect the plus / minus correctly, otherwise it can cause a lot of damage to the motherboard.

    Or, when that works, or like to skip the first idea..
    Try to fix the psu by replacing at least a few caps, a good start are the two 1500uF caps, or else a complete re-cap.
     
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  7. amila4341

    amila4341 New Member

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    I will check that way .
    thank you
     
  8. amila4341

    amila4341 New Member

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    Voltage between 120uf is 260v to 270v .
    is it acceptable
    Update:- when receiver boots power supply output voltage is 12v. then I restarted the receiver it hangs and power supply output voltage is 11.9v what may cause this voltage drop in power supply output
     
    Last edited: Feb 22, 2021
  9. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    That depend how much voltage these caps may have and what the main voltage is.
    But I wonder why you think that it may be this cap, because when you have a voltage drop, than it's most likely a issue from the cold side instead of the hot side of the psu.
     
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  10. amila4341

    amila4341 New Member

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    Update:- when receiver boots power supply output voltage is 12v. then I restarted the receiver it hangs and power supply output voltage is 11.9v what may cause this voltage drop in power supply output
     
  11. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    I already gave a answer to this...
    .....
    That could mean ...

    Or the motherboard consumes too much, causing the 12v to collapse.
    Or the 12v power supply has been weakened, usually due to outdated capacitors
    .....

    But before thinking it's a motherboard fault, you need to be sure it's not caused due the power supply.
    Therefore I had earlier advised to test it with another 12vDc power supply, or recap the power supply.

    If after excluding the psu, it's seems to be caused due the motherboard. then it will be harder, or could even impossible to find.
    Then it may be a motherboard hardware issue as a issue with the tuner/wifi/network/memory or worse scenario, the cpu.

    Or the motherboard needs a recap, or at least the caps checked with a good measurement device which might/can check the caps without removing it from the motherboard, as the MESR-100 V2, but that is also not a easy job.
     
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  12. amila4341

    amila4341 New Member

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    I have replaced all power supply capacitors but problem not solved
    When I switched on box after 4 to 5 hours it boots well and when I restart again it hangs on white light. If I again start box after 4 to 5 hours then box boots.but it can't restarts again
    have to wait.
    Any suggestions please
     
    Last edited: Mar 15, 2021
  13. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    At this point, I can only think of a method that I would try if I had done several things without any improvement, which is to cool the cpu by blowing a fan on it. If that does give some changes, it could be the CPU, bad / outdated solder balls underneath, or surrounding parts next to it.
     
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  14. amila4341

    amila4341 New Member

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    20210331_082137.jpg What are your thoughts on these issues please
    C841,842,843 values?
     
    Last edited: Mar 31, 2021
  15. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Pin 1 and 3 are measured as ground, and 7-8 08.3 ohm which is close to zero ohms and thus may give the idea that it's shorted.
    See here the picture of all these ohms measurements.

    As for the ceramic caps, right now unknown for me and I have some doubts if it's needed in this case.
     
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  16. amila4341

    amila4341 New Member

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    20210516_185553.jpg
    What is the best temperature for hot air gun to remove this ic u 809 I tried 380c to 420 c but not been able to desolder
     
  17. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Normally I use always 360 degrees, but often also use flux, and mostly protect the surrounding area with kapton tape.
     
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  18. amila4341

    amila4341 New Member

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    I removed u 809 ic and 3 capacitors still capacitor pads and u809 pin 1,3,7,8 short is it normal what may cause. What I should check now please 20210517_091758.jpg
     
  19. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yeah well, I have no measurement when the U809 Z1034PI, 12 to 1 vdc has been removed therefor I can not confirm the ohms value without it.
    But still, to me it seems that it should stays low as already was told by me on mar 31, 2021.
    Pin 1 and 3 are measured as ground, and 7-8 08.3 ohm which is close to zero ohms and thus may give the idea that it's shorted.

    Thus be sure it's completely zero ohms, and not low ohms.

    Also, I have never seen the output voltage measurements of this ic, only that your claim that it's shorted.
    I, myself had no reason to think it may defective because as your say, the box starts up after waiting a long time.
    Thus basically, you could assume that it just worked.
    This 1 vdc is used by the memory and cpu, and as far as I know not used for other things than these two.

    The most logic reason why it works when the board is fully unloaded and cold, but failed by a reboot, thus than it's not unload, nor cold, is to think on a bad cap, or some other part which no longer works when it's warm.
    Knowing this, I had do a test with a fan, and plowing first to the cpu, as I already had advised, and wit no success, let it blow to other parts as the memory.

    But still, please be sure that you measured correctly, the ohms value between these are very low, not to zero, but close to it so that in may give the impression that it's shorted.
     
  20. amila4341

    amila4341 New Member

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    Thanks
    What I want to know is it possible to capacitor terminals on c841,842,843 is showing continuity even after capacitors are removed from the board