VU Duo Power Supply Issues / Fixes

Discussion in 'VuPlus Duo Hardware troubles and Repair support.' started by fingersd, Aug 3, 2016.

  1. Jules

    Jules Active Member

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    Hi Fingers, hope you are well.
    After changing many caps in my genuine duo I had a stable and reasonably strong signal for a while.
    Today I notice the picture is pixleating on some channels again and signal fluctuating by about 10 % constantly. Do you think this will be the same caps I have already changed, or something else? Forgot to mention, recentlty changed 2 swolen caps in PSU aswell. Thanks Jules.
     
  2. Jules

    Jules Active Member

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    Hi Fingers and everyone!
    After great success with the Buck reg mod, on one of the Duos, one of the buck regs has blown twice recently.
    It is the 5.2v one. Can you suggest any pointers on this please? I have looked at caps around the board and none look bad. Thanks, Jules.
     
  3. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Hmmm, 5v2 circuit...
    Of what I can tell about it is that it consumes something as 1.5 amps,

    duo-5v-amps.jpg

    For what I measured it feeds the dc to dc ic's and also the U603 5 to 3v and U204, U807 5 pins ic, and U601, u602.
    The good news is, that it seems not to be directly connected to the cpu.
     
  4. Jules

    Jules Active Member

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    Thanks JB great info, I will check
     
  5. Jules

    Jules Active Member

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    Hi JB,
    Have checked current draw from the 5.2v buck reg:
    I get around 1.94 amp without HDD connected and around
    2.4 amp with HDD connected. Just wondering about swapping that buck reg for a 3A rated one instead of the 2A.
    Do you think it's worth a try?
    Thanks, Jules.
     
  6. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    I would first test the receiver without the hdd to know if the dc to dc converter can handle it.
    If it keeps working, then I would use a separate dc to dc converter for the hdd.

    Further it depends which hdd you use, an 5.25-inch drive needs the 5v and 12v and consumes more amps than a 3, 5 inch drive which also only needs the 5v to operate.

    Using a 3 amps dc/dc converter may be enough to feed all of it, however you could also consider to add a heat sink to the dc to dc converter chip/ic.
     
  7. Jules

    Jules Active Member

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    Thanks for the reply Johnny B,
    I have got a heat sinks on all the bucks, but it is a good idea of yours to use a separate buck for the HDD if Duo runs OK with HDD disconnected for now.
    Thanks,
    Jules.
     
  8. Jules

    Jules Active Member

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    Hi JB, have added a separate buck reg for HDD, all working well so far.
    Thanks.
     
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  9. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Perfect, always nice to read that a problem has been solved.
    Thanks for sharing your repair results. :)
     
  10. Jules

    Jules Active Member

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    Thanks JB.