VU Duo dead (red light)

Discussion in 'VuPlus Duo Hardware troubles and Repair support.' started by Zwierbel, Sep 16, 2019.

  1. Zwierbel

    Zwierbel New Member

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    Hello Johnny

    have the problem that one with the C807 already repaired box now refuses service again.
    A renewed replacement of the C807 and the neighboring C814, C850 and all three voltage regulators U801, U802 and U805 including the two Elkos C14, C15 on the power supply (this commodity bloated).
    In addition proactive still the Elkos on the PWS (C12, C16, C17, C18 and C20) as well on the Mainboard C801, C805, C810, C816, C819, C819, C848 were exchanged.
    The problem remains, only the red LED lights up and flashes when a buuton on the remote control is pressed. The hard disk starts up and the CPU warms up. Output voltages at the step down regulators (U801 = 1.280 V, U802 = 1.258 V, U806 = 2.548V) should be OK? Also behind the output coils there is an approximately 0.5 V lower voltage.
    All voltages of the power supply are also there.

    I think by measurement should a defective step down regulator be recognizable? If the output voltages are OK then the regulator should work, am I right?

    Strangely, I measure a resistance of only 5.8 ohms at the output of L803. C819, C820 has been already replaced therfore the low resitance value could com only from C820 or R811 right?

    Does it make sense in this status to flash the JTAG with the Cypress board? The box was not touched by software until the hardware error.

    I get after the input no output on the serial port. Also, the USB port has no voltage. Do you have any further troubleshooting tips?
     
  2. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Q; ...............should be OK?
    Yes these voltage seems to be okay, but I have not see that you have checked the 1.8v output from the u807 and I assume that you measure these voltages after the inductors/zero ohm resistors.

    Q; ...............then the regulator should work, am I right?
    Normally you could consider them as good when it gives the correct output, also when it's connected to the circuit, or not.
    Or it must be frequency related, but when that is incorrect, then the Dc to Dc converter should give a unstable output.

    Q; ..............5.8 ohms at the output of L803. C819
    The L803 coil output should be something as 112 ohm, lower may indicate a issue from the u802 side, or the consumption side.
    More about this, you can see on this ohm/vdc measurements drawing.
    To find this out, then you must separate it from the circuit by removing the F804.
    Often this lower measurements can come from a defective cap, ceramic cap as the c820, or other parts cause it.
    Nevertheless, you must first find out if it's caused due the Dc to Dc converter side, or motherboard circuits side.

    Q; .............make sense in this status to flash the JTAG
    Jtag will probably not work, I expect that it not connect, but it can not harm to try.

    Q; ............no output on the serial port
    When nothing is given, then it could be the nand flash chip, not gives any output data to the cpu.
    Maybe because it has a issue as be empty, no longer data on it, or a issue with one of the eight I/O ports of this chip.
    In any case, it should give some terminal output, after a successfully jtag attempt.
     
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  3. Zwierbel

    Zwierbel New Member

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    Many thanks for your answer!

    ........ the 1.8v output from the u807 and I assume that you measure these voltages after the inductors/zero ohm resistors.

    A; Yes the ouput voltage of chip U807 Pin 1 and 3 is 1.876 V and a liitle bit higher as documented. Measurement on PIN 5,6,7 of U806 shows 1.866 V and seems to be OK.

    ..............5.8 ohms at the output of L803. C819

    A; I'll try to find out where this comes from. First I'll desolder C819, C816, C820 and check again. Afterwads I'll desolder U802 and check again. But for me it is strange the all output voltages are stable in that situation.


    ..................no output on the serial port

    Could you please let me know where the nand flash chip is located, is the U506 ?

    At which time the USB port schould provide 5 V?
    As mentioned I have no voltage on the USB port at the moment, maybe this a a hint.
     
  4. Zwierbel

    Zwierbel New Member

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    Another short question: The serial cable for VU Duo and VU Duo 2 has the same pin assignment?
    Just to be sure I use the right one.
     
  5. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    The nand flash chip is indeed the U506 and as for the serial pins connection for receiving, it's just the pin 2 and 3.
    You need to usea rs232 db9 null modem cable, more about this you can see on this drawing.
    As for the terminal settings, you can see here.
    Usb port question, by only a red led issue it's inactive as also the voltage to it.
    Duo versus duo2 serial cable questing, I'm not sure, but it seems to me logic that they are the same.
     
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  6. Aliraza63

    Aliraza63 Active Member

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    all the vu+ receiver have serial port connection for null model cable are same as its shown in above posts
     
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  7. Zwierbel

    Zwierbel New Member

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    Hi,
    now I got my cypress board and was ablew to connect.
    Unfortunetely the flash explorer gave me the following error: "Maker ID returned from the flash: 93 does not match"

    upload_2019-10-5_12-24-59.png

    Any idea what this could be or else I can try ?
     
  8. Aliraza63

    Aliraza63 Active Member

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    check the pin outs I had the same issue
    normally its an issue C. boards is not getting any link with flash

    update :
    visit this link .. Johnny has explained in very simple but in detail way. u can find the answer.
    Although its an solo2 thread's link but it will help u to give an view how ur box have an issue
    https://jb8a8f8.com/support/index.php?threads/lonrison-solo2-jtag.323/
     
    Last edited: Oct 5, 2019
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  9. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    @Zwierbel
    Maker ID returned from the flash: 93 does not match
    Thus it gets a response from the nand chip, but it basically tells you that the bbs script you use not match the nand flash chip you have on your motherboard.
    My idea, check the nand flash chip numbers on the chip, be sure you use the right bbs script for it.
     
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  10. Zwierbel

    Zwierbel New Member

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    Hi,
    it was very hard to read. My chip is a K9F1G08U0C which is different to my selection in flash explorer (K9F1G08U0A).
    But I have no selection for K9F1G08U0C in flash explorer. Where do I get the right BBS script?
     
  11. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    The bbs K9F1G08U0A should also be suitable for the K9F1G08U0C.
    But just to be sure, I'll give you my K9F1G08U0C script.

    Code:
    <?xml version="1.0" encoding="utf-8"?>
    <Flash maker="Samsung" name="Samsung K9F1G08U0C" type="NAND" technology="SLC">
      <Command type="Nand" programmode="Block" maxbyte="2048"/>
      <ID>
        <Maker maxbyte="1" offset="0x00">0xEC</Maker>
        <Device maxbyte="1">
          <DevId offset="0x01">0xF1</DevId>
        </Device>
      </ID>
      <Size unit="gbit">1</Size>
      <Sector uniform="true" secure="false">
        <MaxSector>1024</MaxSector>
        <Size unit="kbyte">128</Size>
      </Sector>
    </Flash>
    
    Just copy/paste it with you text editor and save it to the,
    c:\Program Files\Broadcom\Broadband Studio 3\Flashes\
    Save it as, Samsung K9F1G08U0C.xml

    Nevertheless, it's further the same Maker ID code etc. the only differences is the Flash maker name.

    If this also not works, and you already use a windows xp system (I'm not sure if it also works on other systems, I always use windows Xp for it) then the only thing it could be is that the nand flash chip has damaged by the ID section, in that case you need to replace the chip for a new one.
    Another thing could be a bad solder on the nand chip, or a bad communication between the nand chip and the cpu, but I assume you already checked that.
     
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  12. Zwierbel

    Zwierbel New Member

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    First of all many thanks for your valuable support and I'm very sorry for my late reply!
    I'v tried so many time intensive tasks, that is the reason why.
    I've tried in the very first step the connection and update with a Windows 7 host. After my problems as mentioned the next actions was performed with a Windows XP VM. With your XML file that fails also.
    As last step I was trying to do the connection and update with a brand new installed Windows XP operating system on a dedicated physical machine and your XML file but this fails also. At the moment I assume it could be a defictive cypress board or as you already mentioned a defective NAND chip. The soldering looks good to me and wasn't touched. I'll get a running VU Duo box at the end of this week and will figure out where the problem comes from.

    An update will follow.

    Best regards
     
    Last edited: Oct 9, 2019
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  13. Zwierbel

    Zwierbel New Member

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    I have now connected my cypress board with another box. That works imediate and shows no problems at all. Therfore I guess the NAND chip of my defective VU Duo is broken.
     
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  14. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yes, could be.
    There are still some other cases which could cause this no nand chip ID, for example an issue with the chip enable/disable pin, or the 3.3v to it, but the next most logic step is to replace the nand chip for a new one.
     
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  15. Bamar7

    Bamar7 New Member

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    Hello... I have the same problem with a vu duo... The voltages are fine and at c819 and c 820 I have 6'5 ohms... I removed r811 l504 and the low ohms are on the side of the cpu... I changed nadn flash and it stays the same and does not come out of red LED... Any alternatives to it being cpu? Thank you
     
  16. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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  17. Bamar7

    Bamar7 New Member

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  18. Bamar7

    Bamar7 New Member

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    Thank you for answering.... The rs232 port gives nothing... The port of jtag has in pin 1-2 and 3 3'3 vol... That's not normal, is it?
     
  19. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    When you measure it correctly than you should notice a slightly differences, the vcc is 3,3v and the Sda/Scl 3.1v or 3.0v

    Did you have replaced the famous cap C807 on the motherboard?
    Even if you have it replaced a while ago, then it may useful to replace it again.
     
  20. Bamar7

    Bamar7 New Member

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    Hola .. Bueno si, he reemplazado ... Ic u801, u802 y u 805 .... condensadores c807, c814, c850, c819 y c820