Vu Duo PSU no Voltage on all pins 5VS

Discussion in 'VuPlus Duo Hardware troubles and Repair support.' started by tomeek.p, Nov 22, 2017.

  1. tomeek.p

    tomeek.p Member

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    Hello,
    I have a problem. In PSU i do not have a voltage all pins except 5vS. I bridge the PSU pin 5VS with CON.

    OPT2 i OPT3 i have a voiltage 4V-5V and in OPT1 i have 0V. In PSU i have empty places VR1 and C02.

    This is clone v3
     
    Last edited: Nov 22, 2017
  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Sorry but for a possible good advice you will have to wait for Friday because I'm not earlier back in my workshop to investigate this.
     
  3. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    I think, check the R40 resistor, see picture...

    Just repaired a psu with this issue, check the voltages 5vS/con cold side.
     

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    Last edited: Nov 25, 2017
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Reading it again, i do not have a voltage all pins except 5vS
    I've made a mistake with the reading, I overlooked the word not.
    So, you have only the 5vS voltage and so forget the above.
    This could be due the Q3 Con circuit switching, but I need to measure some of it to know it for sure, later more about this.
     
  5. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Picture a bit updated, when you remove the J2 wire jumper on one side then you disable the Con-5vS circuit and the psu should deliver all the voltages or at least giving the unstable (pulsing) voltage which depends on the type psu, only the 5vS voltage should not be working.
    When you have no voltages with the J2 jumper wire disabled, then it could be the zener diode ZD1 hot side near opt 1.
    Replace it and check it again.
    But be also sure that there are no issues with the Q1 power transistor on the hot side otherwise it could blow when replacing the zener diode ZD1

    If you want a short cut.. just check the zener diode ZD1 or replace it.

    Nevertheless, since it related to the hot side, be carefully, always unload the C1 400v big cap before you work on it.
     
  6. tomeek.p

    tomeek.p Member

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    Jumper J2 - 107V

    Q1 power transistor
    Code:
    G - 108V
    D - 0V
    V - 97V
    F - 105V
    ZD1 it's ok.
     
  7. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    No clue were you had taken the ground side, but these ground from the cold/hot side are separated but by using the ground (minus side of the big cap) C1 I measure..
    G - 0V (minus side)
    D - 320Vdc
    V - 13.12Vdc
    F - 0V

    This is this with, or without bridging the 5vS-Con.
    Nevertheless a issue with this hot side transistor will results in a death power supply which is not your case.
    You have a 5v issue, that is.. if these 5v also drops when the psu is not connected to the motherboard.
    If it's only drops when it's connected to the motherboard, then you have a heavy load on the 5v circuit from the motherboard.
     
  8. tomeek.p

    tomeek.p Member

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    Ok, now I have made the measurement correctly.
    Code:
    G - 0V (minus side)
    D - 2,2Vdc
    V - 12,67Vdc
    F - 0,15V
     
  9. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    See if you have before and after the rectifier the Ac/Dc voltages.
    Input is Ac voltage colored gray, and after it the Dc voltage colored black/red.
    But be aware that you deal with high voltages, a mistake could give a dramatic result, so be carefully with working on the hot side.
     

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  10. tomeek.p

    tomeek.p Member

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    I have 320V, and i don't have 220V. I only have 110V
     
  11. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Then I assume that your country has 110v instead of 220v.
    As for the 320v Dc, this tells me that you have the 320v Dc but it don't reach the power transistor.
    Check the diode D02 which is placed between the C1 big cap and the Q1 D pin.

    Better would be if you give a picture from your psu print side due the many different psu's.
     
  12. tomeek.p

    tomeek.p Member

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    No, In my country I have 220-230V. D02 is ok.
     

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  13. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Strange that 110v ac issue because I have here a same psu which gives the 233v Ac
    vu-psu-233v.jpg

    But okay since you have the correct C1 cap Dc voltages, but not to the Q1 pin D, let see if you have these voltages after the 204 resistors.
    vu-psu--233v.jpg
     
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  14. tomeek.p

    tomeek.p Member

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    In D02 i have cold solder point. I remove old tin and added a new tin the solder point.
    Before 1,7VDc
    After 320VDc
    Thank you very much. The BOX works! :)
     
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  15. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Hmm, I thought I had already seen a bad soldering on your photo on the D02 resistor side, but had some doubts because it could also be shadow.

    But luckily you have found it by yourself.
    Great job, well done. ;)
     
  16. Layer3

    Layer3 New Member

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    Hi there! Recently I've bought a red light broken vu duo, and thanks to this post I've managed to repair it ( cold soldering in d02 point). However, I am facing another issue... I do not have 12 v coming out from the HDD connector. Neither do I from the 12v point of the rack to the main board... I've managed to have 12 v by soldering a wire from another 14v point from the board and adding a resistor, but it does not seem a very clean repair... Could you please guide me through the troubleshooting please? Thank you very much. Kind regards!
     
  17. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Hi Layer3,

    The 12v delivery comes directly from the power supply.
    Q6, ohm value between the ground and the pin 1 is 27.30Kohms
    Q6, ohm value between the ground and the pin 2 is 3.45Mohms
    Q6, ohm value between the ground and the pin 3 is 6.39Kohms

    In any case, the most common issue if it's failed to give a 12v is the Q6 FQP50N06 60V N-Channel MOSFET transistor.
    Ofcourse for a real test it's often better to remove it, and to check it externally.
     
  18. Layer3

    Layer3 New Member

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    Thanks a lot for your answer! I've been waiting for a new multimeter (mine was broken during current measurements...)

    So I've measured the Q6 and I have decent values on pins 1 and 3, but 0 ohms on pin 2... The point moves freely, and I was wondering to make a bridge connection to the next point. Do you know to which point is pin 2 connected (the middle pin)?

    Thank you very much for your help!
     
  19. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Hmm no ohm measurements onto the Q6 center pin is a bit strange because even if the Q6 is interrupt internally it should still give some ohm value from the D10 or IC5 or other parts as caps which are involved with this circuit.
    Most logic thing it than could be is a interruption somewhere close to the Q6.

    If it's fluctuating, and thus it gives no final good value, then it could be a defective part as maybe the Q6 or the D10.

    In any case, I have here a picture which gives a idea of were it goes, just follow the colored dots, it's from a clone psu, but should basically the same.
    If you have a original psu and want to know were it's going to, then you have to wait until tomorrow.
     

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  20. Layer3

    Layer3 New Member

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    Finally I fixed it! Ok fact the middle pin was not in contact with the other related points, so I have soldered a wire and now I have the 12v. I send you a picture of the fix. Thank you very very much for your help!
    IMG_20180729_223723.jpg
     
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