Palit RTX3080 PCI-e not detected

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hello to all friends.
When I looked at the motherboard visually, one integrated was broken.

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After 3-4 days of research, I found what it was.
2 input and gate logic. NL17SZ08. marking code L2

this circuit is related to pcie rst signal. I could not find the same logic. i replaced this logic instead - MC74VHC
MC74VHC- 2 input logic and gate

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all voltages are active on the video card.
gpu is normal hot. Ohms are all normal. no short circuit. only the motherboard is not detecting the video card.
I'm only getting images from the vga port on the motherboard

When I examine the eeprom with the oscilloscope, there is no reading.

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帮他翻译了一下

各位朋友好  当我目不转睛地看着主板时，

一个集成电路板坏了  经过3-4天的研究，我发现了它是什么。 2输入和门逻辑。NL17SZ08。标记代码L2 该电路与pcie rst信号有关。我找不到同样的逻辑。我替换了这个逻辑——MC74VHC

视频卡上的所有电压都处于激活状态。 gpu通常是热的。欧姆都正常。没有短路。只有主板没有检测到显卡。 我只从主板上的vga端口获取图像 当我用示波器检查eeprom时，没有读数

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厉害了厉害了看不懂

                               
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会员1399464

Hello. If the GPU is not getting PEX_RST_BUF* signal, the EEPROM will not be read by the GPU so it's expeceted that you won't see anything on it.

If you are getting the RST signal from your motherboard at pin 1&2 at the AND gate, then you should be getting the buffered version of the RST signal at pin4, which goes directly to the GPU via a resistor ( looks like the one sitting diagonally to the right of the AND gate in your photo). You can take off the resistor and check the pad connecting to the GPU to see if well soldered on the GPU side.

If it looks like the GPU is getting power normally, and it's getting clock from the crystal on board, and the buffered RST is going to GPU, assuming some peripherals (power control I2C, temp, etc.) are good, a good GPU die shall try to read from BIOS EEPROM at this point.

Hope this helps.

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拔掉内存电流不动

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vusalcrm 发表于 2022-2-26 23:39
i check resistor 100k- it is OK
pull down res.  this is resistor 1 pin connect GND.

You are right, that is a pull down resistor. But did you verify the signal (non GND terminal) is going into the GPU correctly? You can do that be measuring the reverse bias diode resistance of it to GND using a DMM's diode function. If connection is good, it shall read 400 Ohms ~ish if I'm not mistaken.

Beyond that, did you verify this AND gate's pin 1 and 2 are getting the reset signal (PEX_RST_AND*) correctly? Not sure about your particular board but on my reference it is coming from another AND gate on the other side of the PCB (U54). It is an AND of the reset signal from PCIE connector (PEX_RST*) and 3V3_SEQ. You can bypass this AND gate by populating a 0 ohm resistor to R711.

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看不懂，谁懂？给我们说下

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你翻译给他说 鬼佬来迅维学校系统学习吧。别再瞎搞胡搞了！

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ROM芯片测不到波形，ROM对地电阻可正常，再测试gpu工作条件，还有27M晶体有没有波形。再不行50包邮我回收了

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等高手来判断

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Poko 发表于 2022-2-26 09:05
Hello. If the GPU is not getting PEX_RST_BUF* signal, the EEPROM will not be read by the GPU so it's ...

i check resistor 100k- it is OK
pull down res.  this is resistor 1 pin connect GND.

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youyafei 发表于 2022-2-27 09:18
ROM芯片测不到波形，ROM对地电阻可正常，再测试gpu工作条件，还有27M晶体有没有波形。再不行50包邮我回收了

27mhz signal ok

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check the No.4 pin of NL17SZ08, if that is high level (3.2V), that is OK, if not, check the resistance by your DMM with no power. as usual, GPU pin broken (short) will cause that.

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testpoint 发表于 2022-2-28 06:49
check the No.4 pin of NL17SZ08, if that is high level (3.2V), that is OK, if not, check the resistan ...

and gate logic check
1-2 pin > 3.3v OK
4 out - 1.8Vv OK
5 VCC - 1.8v OK

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This model does not have a boardview file. but compatible with msi model
rtx3080

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Poko 发表于 2022-2-27 09:43
You are right, that is a pull down resistor. But did you verify the signal (non GND terminal) is g ...

This model does not have a boardview file. but compatible with msi model
logic 1-2pin 3.3v ok
u54 without  - R711 with - 3.3v send

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FBVDDQ - 63.8ohm - diode - 0.094
NVVDD - 0.3ohm - diode - 0.002
MSVDD- 0.5 ohm - diode - 0.002
PEX_DVDD - 8.1 ohm - diode -0.015
1V8 - 313 ohm - diode -0.341
5V - 319 ohm - diode - 0.526

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vusalcrm 发表于 2022-02-28 16:46
This model does not have a boardview file. but compatible with msi model
logic 1-2pin 3.3v ok
u54 without  - R711 with - 3.3v send

so you can see the buffered reset signal going into GPU toggling when power on using an oscope, and bios Flash is not getting anything? No CS no MOSI no CLK?

Then some peripheral fault condition is stopping the GPU from initialization...

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1V8 - 313 ohm - diode -0.341
1V8 power's res is  abnormal，normally it will be 10~30k ohm or above.The GPU may be damaged。

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Poko 发表于 2022-2-28 18:19
so you can see the buffered reset signal going into GPU toggling when power on using an oscope, an ...

CS no MOSI no CLK - I checked the start time with an oscilloscope.
There is no data reading other than voltage. there is only constant voltage