Problem with DUO - only red light, the light TJ-45 is on.

Discussion in 'VuPlus Duo Hardware troubles and Repair support.' started by tomeek.p, Oct 26, 2017.

  1. tomeek.p

    tomeek.p Member

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    Hello,

    in this thread i have problem with vu+ duo. Box show only red light. When I press any key in remote control led blink to green. Leds on Port Ethernet is on.

    I connected bcm with memory. Flashing cfe but box not started

    I checked:
    U801, U802, U805 F803, F804, F812 voltage is ok.
    U807, U806, C545 voltage is ok.
    First Pin jtag have 3,3V
     
    Last edited: Oct 26, 2017
  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    First I need to know if you have a clone, or a original box but this concerns both,
    Renew the Cap C807 for a 330uf 25v or other cap as the same as on the motherboard, but better is a bit higher.
    This is often the issue.
     
  3. tomeek.p

    tomeek.p Member

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    This is original. I renew the Caps C807, C814, C850. Still only red light. I check the fuses F803, F804, F812 and F813 Voltage in this fuses is ok.
     
  4. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Then it becomes more difficult to find the issue because it could be some other capacitor, can't say which, or the cpu with some bad contact to the motherboard or the famous nand flash chip issue.

    Assuming that you already have tried to connect to the box with an rs232 terminal program and got no received output, Than the best next step is to jtag (I2C) the motherboard with the cypress interface to see if it want's to connect to the bbs software.
    If so, the it could be the nand flash chip.
    If not, then it's most likely due a cpu issue.

    If it's connect and you have access to the nand flash chip then I mostly erasing the chip to see if there are any issues with it and uploading the boot loader.
    When that succeeded, then you should be able to upload a image file to the box on the regulair way with the usb.
    If it can't upload the boot loader, then the nand flash chip needs to be replaced for a new one.

    This is the most logical step to know if it's one of these cases to knowing if it's related to the cpu, or nand flash chip befor to think on another hardware failure.
     
  5. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Ah, didn't noticed that you already have done the jtag process with success and assume that you used the correct boot loader for the original box.
    In that case, check/replace the rs232 serial chip because it may block the boot up from the box when it's defective.
     
  6. tomeek.p

    tomeek.p Member

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    I exchanged nand memory. The new and old memory sometimes shows that the stb was disconnected. When uploading cfe, sometimes it is the same. Looks like somewhere lost voltage.
     
  7. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Maybe because you use four wires with jtag.
    Disconnection while uploading with the bbs software may happen when you connect the cypress board with four wires.
    I always connect only the Gnd/Sda/Scl and never the vcc wire.
     
  8. tomeek.p

    tomeek.p Member

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    I do not connect vcc to debug socket.

    Maybe i have invalid cfe file, download this file from vu+ official site. Maybe is old? I don't know.
     
  9. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yeah I can only say it for the clone because I have repaired most of them and a few originals.
    But as far as I remember it should be the 750_cfe_3_0_111012_release.bin file
    file size is 287.604

    This I always used for the jtag job,

    Otherwise, when disconnect it could be the cypress usb driver.
    In any case, when connected it should be recognized into the Usb controllers as the Broadcom test adapter.

    Or else, a issue with the 3.3v circuit, or when it's were a clone a issue with the security chip.

    Other thing it could be is a issue with one of the four I/O data connections between the nand flash chip and the cpu.
    They should be all in the same M ohm range.

    These are just some ideas what it could be, but I'm more thinking that it's caused due the cpu, probably bad outdated solder ball(s), or the motherboard has some track issues.
     
  10. tomeek.p

    tomeek.p Member

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    I connect RS. Putty show only this:
    Code:
    BCM73350010
    012
    Shmoo Version=1.9
    
    MEMC-00000000 RW=00000010 WW=00000047 G=00000001 R=00000008 W=00000015
    MEMC-00000001 RW=00000010 WW=00000055 G=00000001 R=00000009 W=00000000 #$
    3
    COPY CODE
    A567
    
     
  11. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    What I mostly do when I see this is to add some pressure on the cpu and see if it's gives more output in the terminal screen.
     
  12. tomeek.p

    tomeek.p Member

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    Putty don't display nothig new.
     
  13. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yeah, it's become difficult when you already have replaced the famous c807 capacitor without results.
    In some cases it could also help by replacing the C814 but it seems that you already have this replaced.
    Maybe has the U801 Dc/Dc regulator some issue, or one of the two coils has no longer the correct value, it could be internally shorted/damaged due overheating by a to heavy load.
    If you have not a spare board, then you could consider to swap them from the other circuit.

    https://jb8a8f8.com/support/index.php?attachments/vu-_duo_5v2-to-u801-802-803-jpg.131/
     
  14. tomeek.p

    tomeek.p Member

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    In marked places I have a short circuit to ground.
    duo.png
     
  15. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Not so best if they all shorted, it mostly could happen after a cpu reflow job which went wrong.
    Solder had become to liquid and created several shorts under the cpu.

    To know it for sure, then the best way is to disable one side of the mainboard the output coils L804/803/805 to know if it not accursed from the dc/dc ic's.
     
  16. tomeek.p

    tomeek.p Member

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    I soldered the L804. On the pad marked on the yellow I have a circuit to ground on the pad marked in blue I do not have circuit to ground.
     

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  17. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    In that case, and if it's only accursed with the u801 voltage circuit output the it could be a shorted cap c810/c811 or c812 or else it could still be the cpu, this voltage feeds to the center area of the cpu.
     
  18. tomeek.p

    tomeek.p Member

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    I soldered yet the L803 and L809. I have a circuit to ground on caps C856, C868, C810, C846, etc. In caps C805, C841, etc. everything is ok.

    I do not know if I think well. Does any capacitor circuit to ground?
     
  19. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Normal and ceramic smd caps are mostly on one side connected to the ground.
    A normal cap has a plus minus side just like a battery and needs to be correctly mounted.
    A ceramic cap does not have a plus/minus side, so it doesn't matter how it's placed.
    A normal shorted cap does not happen often, but a ceramic smd cap may when it's defective create a short between a voltage circuit and the ground.