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Samsung np800g5m odyssey / ba41-025490a / no image

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    Samsung np800g5m odyssey / ba41-025490a / no image

    Guys, how are you? I really need your help.


    This Samsung laptop came with the problem of not recognizing the GPU. Apparently, it is a recurring defect in this series. Before working on the motherboard, I noticed some problems before.
    The laptop turned on, generated an image and worked perfectly, but without recognizing the GPU. There were voltages in their inductors, memories and capacitors on top of the chip. I realized that at some point, when turning on the notebook, the GPU passed 100 degrees with 3 seconds after turning on, when the note turned off and continued turning on normally ... This did not always happen. Remembering that when the GPU reached this temperature, the consumption exceeded 4A in the power supply.

    I removed the GPU. The solder on this motherboard is very hard, it looks like it has glue, bad to work with. This GPU is very close to the CPU, which is an I7 HQ, a huge chip. There are some facts, I will leave a summary at the end of the text.
    I did the reballing on the GPU, with no hope of its operation, because with the symptom of getting too hot when turning on the laptop, I didn't even count on it working, but I did the reballing anyway, my mistake.

    The laptop did not generate an image.

    The laptop turns on, generates all tensions, but does not generate an image. CPU and GPU at normal temperatures. The GPU symptom did not happen again.
    -----
    • I have already isolated the GPU by removing the power inductors, I have already removed the GPU and turn on without it too.
      I have already rewritten Bios (with the only file found) and Super I / O as well.
      I realized that there is no selftest pulse of vccGT that you have on these processors when you turn on. I know that there is only tension in the GFX when it is in the operating system. But when you call, there has to be a brief pulse. There was a laptop(Acer) here with the CPU of the same generation, the pulse is close to 900mv for about 175ms.
      I changed the eeprom. The original is a Gigadevice GD25Q64C, I replaced it with a Winbond 25q64fvsiq, which would be compatible.
      I made clear ME in the downloaded and original BIOS.
      I realize that when I turn it off, either by the power supply or by holding the button, the screen flashes quickly.
      I checked the crystals, everyone is OK.
      The processor has 3 phases for CPU_Core and 2 for GFX. I removed the 2 GFX and "borrowed" one of the CI's from one of the CPU phases and put it in the GFX. As it is the same, there is no problem and the CPU would work with 2 phases, for testing. And it didn't work either.
      I realized that, as the GT is missing the pulse, repairing the cpu_core Ci's operation, on pin 1 there is a pwm signal, with oscillations. In the GFX, this signal is fixed, without oscillating. Makes me suspicious of the processor controller.
      When turn on the motherboard, the consumption goes to 1.35A ~ 1.3A, 21 seconds later it drops to 1.08 ~ 1.10. It increases very slowly according to the temperature, rising naturally.

    ---
    Some components:

    Processor controller: ISL 95855 (I didn't find datasheet)

    Processor phases: 59924M (not found datasheet)

    GPU: GTX1050

    CPU: SR32Q (i7-7700HQ)

    SHP: SR30W (HM175)

    GPU phases: Z1237QI2
    ----

    I found neither a schema nor a boardview for this card. And bios I found only one.
    Last edited by SMDFlea; 08-29-2020, 01:59 AM. Reason: type error

    #2
    Re: Samsung np800g5m odyssey / ba41-025490a / no image

    possibility of damage gpu .. removing the gpu with glue can damage and lift some pads. did you inspect the board for damage and lifted pads? why reball it? removing it has the possibility of gpu damage specially if it has glue on a lot of stress to the gpu. what temperature value before the gpu is lifted? what temp profile did you use? try to replace with new gpu if possible..
    Last edited by piernov; 09-02-2020, 08:49 AM. Reason: remove full quote of OP
    Never stop LEARNING because life never stops TEACHING!

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      #3
      Re: Samsung np800g5m odyssey / ba41-025490a / no image

      Originally posted by Duranitron View Post
      possibility of damage gpu .. removing the gpu with glue can damage and lift some pads. did you inspect the board for damage and lifted pads? why reball it? removing it has the possibility of gpu damage specially if it has glue on a lot of stress to the gpu. what temperature value before the gpu is lifted? what temp profile did you use? try to replace with new gpu if possible..
      I changed the GPU, the symptom remained the same. I am suspicious of the BIOS, because I re-recorded it with another file and the symptom changed. With another file, consumption reaches 1.7A and when restarting, the led flashes twice, instead of 4.

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