Fault finder

Discussion in 'DM800HD-E Schematic drawings, Pcb images etc..' started by Johnny B., Jun 18, 2015.

  1. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    If you have problems with your motherboard than it is wise to measure all the main voltages.
    There were a fault finder for the 800 HD as from Ferrari and the original box, but these are different.

    One note, hopefully you have no issues with the voltages because most of the Dc to Dc ic's are unknown.
    However I have a alternative solution, this I will post later.

    Good luck...

    DN800HD-Estar-Faultfinder.jpg
     
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  2. didier.delaey

    didier.delaey New Member

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    ok, didier here
    the five IC ùarqued AAxxx are SY8133 from the company silergy, I found on aliexpress by 10 pieces for a very few euros.
    I replaced sucessfully the 2.5V and the 5v at the bottom side of the print.
    I have problem with u22 5V on the top cannot start.
    If looking onthe datasheet you will found that the pin 8 is the chip enable and should be high.
    I don't understand why on U22 we have 1megohm 105 to the ground pin 8
    all the other 4 IC have 103 10kohm between pin 8 EN and supply pin 7 and i will change remove r82 and place 103 resistance between 7 and 8 to check if this solve the problem.

    see datasheet sy8133 remount_aud

    regards
    didier delaey
     
  3. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    This is because the U22 pin 8 has been set to low, see the resistor r82 (value code 102) which is placed between the pin8 to ground, and see the U24 R296 (value code 103) which is placed between the pin 8 to 12v pin 7.

    In any case, if your SY8133 can handle the 12v on pin 8 then remove the r82 and place it between the 12v input pin 7 and 8.
    Then the U22 ic should become active.

    Also, there is a difference with the print site they are AUW while on the parts side they are AAW.
    And the AAW pin 8 (I think) does not matter if it's low or high while the AUW must be set to high.
    That's the reason why your U22 replacement ic stays inactive while the replacements on the others works.
     
  4. didier.delaey

    didier.delaey New Member

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    I start my researh with aaw1qa then aauoua, i order sy8133 and get aaw3wa on other dm800 other number,
    i will tr tomorrow and tell you what results are
    best regards thanks for the answer
    didier delaey
     
  5. Johnny B.

    Johnny B. Technical Support Staff Member Moderator

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    Yeah basically you should use a Dc/Dc replacement chip which is active low instead of active high.
    But keep also in mind that the coil, in this case L38 100uH may also be wrong for your replacement ic.
    But this you could see in the datasheet, and since they are also used on the print side then I think that this should not be the issue.
     
  6. didier.delaey

    didier.delaey New Member

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    I confirm both estar have now 5v after changing R82 to pin 7 12v.One estar is working perfectly now, the other has a microprocessor damaged with IO port.If you have message Multimedia error after flashing ok, the sim card is bad.I found on dm800pvr that I lost a few mV on the connector power bloc 11.94v and 12.05 on the pin.After soldering the rivet it is ok 12.05V on the motherboard + diode side.This unit is a good quality one, I thing it is manufatured by Dupengda.
    Best regards didier Delaey
     
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