Vu+ Duo red led jtag ok, only garbage on rs232

Discussion in 'VuPlus Duo Hardware troubles and Repair support.' started by pnung, Nov 4, 2018.

  1. pnung

    pnung New Member

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    Hi.
    My Box vu+ duo genuine box, have the red light Problem.
    Voltages are right. I renewed u801 and u802 already to be sure they are not the problem, voltages on u801 and u802 Port 7 and 8 are 1Volt should this be 1.2 volt?

    I can write Bootloader file with jtag.
    Voltage on vcc jtag Port is 3.3 volt!
    But on serial sub d 9 connection i only get multiple lines of garbage and after some lines it stoped.
    CPU is heating and broadcom 3 studio get connected to jtag and flash Explorer detect flash Chip right!
    Any ideas what i can Check?

    I already replace the three 220mF capacitores *c807 c814 and 850. Also replaced 1000mF c819 and c848.

    Kind regards.
     
    Last edited: Nov 4, 2018
  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yeah, when the Rs232 ic already had been replaced, and it didn't helped, than it's possible that it's caused by the cpu bad pin connection.
    Nevertheless check at least the rs232 pcb before thinking of a other case.
    For more info about this, see the Vuplus serial port information topic.
     
  3. pnung

    pnung New Member

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    Hi. I found a Problem with the c399 near the x301! The ceramic capacitor is missing... and one solder pad is pulled out of the board :(
    Some body know where the c399 solder pad (CPU side) goes to ...

    Kind regards
    Pnung
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    This goes to a R34 cpu pin, and on the other (print) side to the R307 > C3101 - X301 pin.
    All close to the X301 print side.
     
  5. pnung

    pnung New Member

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    Nice. I take c399 from a broken CPU mainboard and Bridge the broken c399 contact to the rear side ... and what should i say i'm a big Step to success... I See starting in Display:) :) but it hang there ... I think i musst reflash Box by USB... I will try next...
    Question is can i solder c399 capacitor side to x301 leg (underside) for better contact ... my multimeter say direct contact to x301 leg from c399 capacitor ... so far thank you very very much!!! I attached 3 Pics dir better unterdtabdubg ...
     

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  6. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    The c399,
    One side is going to the L301 parts side, the other side of the c399 to the R307 print side etc.
    So yes, if you place the c339 on the print side, then you need to wire the other side to the L301.

    duoSnapx301.jpg
     
  7. pnung

    pnung New Member

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    As you suggest i solder on R307 on backside and fix the cable with some hot glue.
    Box installing Software via USB Stick.
     

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  8. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Nice job, well done.
    And does the box works when you have flashed it with a fresh image file?
     
  9. pnung

    pnung New Member

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    Great!! Box work great!!! :) :) thank you for perfect Support from your side.
    So if some body dont find red led Problem look on mainboard, if some ceramic capacitors missing ;).
     

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  10. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Cool, congrats with the repair results. :)
    Enjoy your victory and thanks for sharing your repair results.