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,
    I have now received the Buck components to have a go at replacing PSU. I will make a start.
    Looking at the pic you posted replacing the caps on the original PSU you have marked a few 1000uf caps but they seem to be 2200uf on my PSU's.
    Regards, Jules.
     
  2. fingersd

    fingersd Member

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    Re your caps, your board is probably an upgraded one, as these are for smoothing ripple in the supply, anything above 1000uf would probably do the same job, 2200uf would probably be an improvement.

    Good Luck with your rebuild, let me know if you get stuck.
    Just a few tips

    Use ohms range on multimeter to check there are no shorts between different voltage rails before adding your regulators.
    Remember to set all voltages prior to powering on
    I usually set mine slightly on the high side 5.1v 3.4v
    As stated earlier, remove everything except the jumper shown here.

    [​IMG]
     
    Last edited: Feb 20, 2017
  3. Jules

    Jules Active Member

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    Thanks for your help fingers,
    I will keep you informed of my progress.
     
  4. Jules

    Jules Active Member

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    Hi fingers, sorry it's been a while but I have now mounted the 5 regs on the pcb, wired them up and adjusted to correct voltages a touch over as you said: booster 34.1v the others: 12.1v, 5.3v, 3.4v and 5.1v.
    tomorrow hope to install in Duo. I'll keep you posted.
    Thanks again,
    Jules.
     
  5. fingersd

    fingersd Member

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    Good luck, Let us know how you get on..
     
  6. Jules

    Jules Active Member

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    Will do Cheers.
     
  7. Jules

    Jules Active Member

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    Hi Fingers,
    Success! Although I haven't connected to TV yet. Channels showing and changing in display also.
    I checked voltages before connecting, but when I first powered up all the voltages for a few seconds were a few volts high but from then on they seemed to stay correct. Attached pic. As you can see I used a different board to mount the regs (an old facia from a Ford radio, I repair and decode radios) I also put an in an inline switch for the mains power. Thanks again, I'll try other things shortly and report back.
     

    Attached Files:

    Johnny B. likes this.
  8. fingersd

    fingersd Member

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    Well done Jules.
    The method of implementation is unimportant, the end result is all we are really interested in.
     
  9. Jules

    Jules Active Member

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    Been working with TV for about an hour now all stable. It seems so much more responsive with the new PSU.
    You may remember I bought 2 of these faulty boxes, so I have just ordered more regs to repair the other one
    Thanks again matey. I wonder what the power cosumption is compared to the original PSU?
     
  10. fingersd

    fingersd Member

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    No idea sorry, I'm in the UK at the moment and my Duo's are in Spain so I can't put a meter on mine too check.
    I would expect the Bucks to operate @ about 90% efficiency, so maybe a slight increase.

    the Duo is rated @ about 26 watts in use (let's say 35 - 40 if recording to HDD and streaming) add 10% for the inefficiency of the regulators, I would expect never more than 45 watts full load.

    If shopping for a laptop PSU 3.34A 65W should be ample, you may even be able to use lower, but not sure it's worth the economy as laptop PSU's run hot anyway.

    If your building another, It may be worth considering a 12V PSU and save yourself 1 buck converter

    Glad it's working though. To my knowledge your only the 3rd person to attempt this Mod


    P.S. after a couple of hours use, it may be worth switching off and feeling the LM2596's to see how hot there running (if over hot, fit heatsinks)
    http://www.ebay.co.uk/itm/20pcs-DIY...113945?hash=item2cb6e666d9:g:Z1YAAOSwA3dYR-PL

    if there running hot it may indicate you have a bad capacitor somewhere
     
    Last edited: Feb 21, 2017
  11. Jules

    Jules Active Member

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    Thanks for the tips Fingers.
    I will check to see how hot they are just in case.
    Maybe worth having fan running constantly?
    Regards,
    Jules.
     
  12. Jules

    Jules Active Member

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    Thanks, they seem quite hot. For now I set the fan to constantly which is helping.
    The heat sinks in the link you sent me, I suppose I need to fix them to the IC on each Buck reg?
     
  13. fingersd

    fingersd Member

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    I've been running mine (when I'm there) without heatsinks with no problems for 6 months but had noticed they ran hot (especially the 5v rail) so decided to add heatsinks myself.

    Rather than order any I hacksawed an old cooler I had knocking about and superglued them to the top of the LM2596's.
    they have been in place for a further 3 months without issue.

    The fault may be that many of these cheap Chinese LM2596 IC's are actually fake and unable to handle the advertised current.

    The fan can't hurt, but I don't remember ever setting mine to run constantly from within the OS
     
  14. Jules

    Jules Active Member

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    Thanks again for th info. I have adhesive here so I have ordered the heat sinks from the link you sent.
    I notice though, that they are 14mm . Don't think they will fit to side on 1 side may need to trim by a few mm.
     
  15. fingersd

    fingersd Member

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    again can't help there as I made my own. There may be cheaper or a better size available, I didn't do much searching. they will be easy enough to cut though
     
  16. Jules

    Jules Active Member

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    Yes no problem to cut one side just enough so it fits on the chip. I have left fan running for now, its a lot cooler.
    Thanks again Fingers, I'll kep in touch.
     
  17. fingersd

    fingersd Member

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    No problem at all.
    I hope you enjoyed the build and maybe learned a little along the way
     
  18. fingersd

    fingersd Member

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    Jules, just a final thought, try to establish which regulator runs the hottest (probably the 5v) and in your next build locate that regulator directly in front of the fan.

    It's bound to help a little.

    Also, mark your PCB with the regulator output voltages, it'll aid future fault finding.
     
    Last edited: Feb 21, 2017
  19. Jules

    Jules Active Member

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    Great info as usual fingers thanks.
     
  20. Jules

    Jules Active Member

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    Hi, again Fingers,
    I found some heat sinks on an old circuit board, cut them to size and fixed them to the reg chips.
    Hopefully this should do the job. I also checked the voltages again, they seemed to have dropped by about 0.1 to 0.4. I suppose this is normal? They probably fluctuate. Attached new pic with heat sinks. Thanks again matey.
     

    Attached Files: