Duo2 water ingress

Discussion in 'VuPlus Duo Schematic drawings, Pcb images etc..' started by Willow5, May 28, 2020.

  1. Willow5

    Willow5 New Member

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    Hello. My Duo2 has suffered water ingress and this has corroded some of the circuitry near the tuner area. Since I am not familiar with the schematic, please can anyone kindly advise if R801 is missing from this picture and whether a leg from the power IC is missing. They both look suspect to me.

    If I move the tuner to the next slot, would the tuner still work despite these issues?
     

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  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yes the R801 is missing and at least the leg of the U801 has gone which may be a ground pin.
    You can take the values and circuit measurements from the U803/R851, this is a same setup.

    Tuner, next slot question,
    Theoretically it should work if the U801 circuit has no short-circuit and the tuner itself has not damage.
     
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  3. Willow5

    Willow5 New Member

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    Thank you @Johnny B. Unfortunately I have bigger issues as the whole unit does not power up at all. I replaced all the capacitors in the power board and getting the 12v output but nothing is on not even the fan. How do I troubleshoot further? I already looked at your guide but I have no voltages on the main board, resistances check out fine.
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    When all the Ohm values are into a same range but you have no Dc output voltages from the Dc to Dc step down ic's, then the most logic thing to think of is to check the input voltage of these Dc to Dc step down ic's.
    When not present, which you may expect when you have no voltage outputs, then it could be just a on/off switch issue, or a 12v input connection interruption to some Dc to Dc step down ic's as the (I thought) u705/u825/u803, others may operate with the 5v input.
     
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  5. Willow5

    Willow5 New Member

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    Thank you @Johnny B. Can you be a bit more specific about what components and pins I need to be testing please? The main 8 pin connector to the motherboard is live with 12v input but from there I lose almost any trace of any voltage at all locations I tested
     
    Last edited: May 28, 2020
  6. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    As for the 12v input, and where it all goes I can't give you more information than I already mentioned.
    If you want to have a more precise (sort of schedule) of the 12v circuit, as were it all goes, it can not be sorted out earlier than the coming weekend or even a little later as on Monday.
     
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  7. Willow5

    Willow5 New Member

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    Thank you @Johnny B. By Monday would be fine thank you. Are there any other simple checks I can do in the meantime? It looks like the tuner side of this board has had some catastrophic failure but I am hoping thest of the circuitry has not suffered too bad, it looks visually ok.
     
  8. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    As far as I know, there should be (I think) also a 12v delivery to the tuner slots, and maybe also to the input of the damaged tuner ic.
    In any case, it seems to me wise to remove this U801 ic, because it's damaged, and maybe cause some issues to the 12v circuit, in any case check at least the damaged area, compare it a bit with the U803 circuit.
     
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  9. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Later I will add more to it, but for now you have a good overview of all the voltages.
    In any case, the 12v input delivered most of it directly to the other dc ic's, so it's a bit strange that you not have it to the ic's.

    To see the full view, click on the picture...
    duo2-printside-vdc-overview.jpg
     
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