• Change PCI device ID of 8800m GTX

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#1 Change PCI device ID of 8800m GTX


by maxwell22 27 June 2016, 10:58
Hi!
I have a problem with my Clevo nVidia 8800m GTX.
It should have the PCI device ID 0x060C but actually has the ID 0x040C.
I already tried to change it with the setpci command under linux and with nvflash under windows but it didn´t work.

I guess, the ID is partially set by resistors as it is done in the schematics of the 8600m gt and the 8800m gts.
Unfortunately I didn´t find any schematics for my 8800m gtx.

Does anybody know, how to find out, which resistors are responsible for this?

Some information, how I think, it came to this wrong pci device id:
My video card was damaged, because it just operated in the lowest possible clockrate.
So i sent the card to a service center for repair.
They weren´t able to repair it, but didn´t want to give me my money and video card back. I think because they changed the gpu and invested some work time.
Finally I got it back, but it was willfully damaged.
They destroyed a coil of the 2 phase converter, deleted the bios and apparently changed the pci device id.
I exchanged the coil and flashed a new modified bios with 0x040C instead of 0x060C as pci device id. Now i got it work again, but only in a "balanced performance mode" because of an invalid MXM Structure. I guess, thats because i just changed the pci device id within the bios, without changing any checksums.

So i guess, they also removed or exchanged a resistor in order to change the device id. It´s just one bit if you compare the id´s:
Code: Select all0x040C -> 0000 0100 0000 1100
0x060C -> 0000 0110 0000 1100


Re: Change PCI device ID of 8800m GTX


by Google Adsense [BOT] 27 June 2016, 10:58

#2 Re: Change PCI device ID of 8800m GTX


by maxwell22 3 July 2016, 13:44
I have made some progress.

I have found some schematics for similar video cards.
These are the
- NB9E-GTX (LS-4471P) with the GPU G92-740-A2, which is ident to my G92-761-B1 chipset
- NB8E-GT
- 8600m GT (LS-354JP)

They all have in common, that the resistors, responsible for the pci device id, are connected to 3.3V_Run and directly with the GPU which has an internal pull down.
The resistors have 2.2k or 2k Ohm (pulled to high) and are otherwise not mounted (pulled to low by GPU).

So I guess, one of my pci device id 2.2kOhm resistors has been exchanged by an ~MOhm resistor.

I have attached the front and back board view with marked resistors.
Red = V3.3_Run
Blue = GND

Image
Image

At the moment I don´t have the right equipment to solder/desolder the resistors quickly.

What would you say, which resistors are hot candidates for the pci dev. settings?

In the NB9E-GTX (LS-4471P) schematic there are also some strap pins, which I can´t assign to some functionality:
- PEX_CFG (1 bit)
- PEX_PLL_TERM (MIOAD0) (1 bit)
- MIOAD6 (1 bit)

Does somebody have an idea what these straps could possibly describe?

Re: Change PCI device ID of 8800m GTX


by Google Adsense [BOT] 3 July 2016, 13:44

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