gtx 970 Repairing a MSI GTX 970 4 GB - Short on the PCI connector!

[SHCreeper]

Greetings and thank you for taking a look! 

My skills: I'm an tech enthusiast but an amateur when it comes to GPU repair and electronics in general (had some classes in the past going over the basics).   

My issue: My graphics card causes issues in my PC where it will shut down the whole system when I have the 3x2 PCI connector connected. If I only have the 4x2 connected, then the PC will stay on without any output to a monitor. Another graphics card will work just fine.   

What I found so far:
- I found that two of the 3x2 connectors have a short between the pairs as seen here in red (pictures below)
- The board seems to be in a generally good condition (pictures below)
- I checked the mosfets similar to this video: https://www.youtube.com/watch?v=hTPAW0J7NKE and found no shorts there. (Here's a big image with what I assume to be the gates and the PCB lanes I checked marked with green circles and arrows)
- I checked the 12V PCB lanes (3 left lanes and 4th from the right) which did not short either

I would really appreciate some pointers on either where to check or a good source with more information on how to continue my hunt! It seems my google-fu is at its limit.

 

Connectors have a short:

https://i.imgur.com/6qXXD15.jpg 

 

Condition of the board:

https://i.imgur.com/MhUtjSz.jpg

https://i.imgur.com/PsgMEQ8.jpg

 

 

 

 

[IkeaGnome]

I'm at work so I'm in and out and dealing with foggy brain today. I'll look over schematics as I have a chance, but so you can get started on it, here's what I have for a 970 4gb using the PG401 board.

 

Edit: it appears you have the 1.3 revision of the board. I'll leave revision 2 up there anyways though. Page 29 will walk you through what the 2x3 connector goes to. 

MS-V317 REV 2.0.pdf MS-V317 REV 2.0.cad

MS-V316 REV 1.3.pdf MS-V316 REV 1.3.cad

[IkeaGnome]

Do pins 4 and 6, bottom left and bottom right of the 3x2 connector short to ground? The only thing those two sets of pins have in common, but don't share with pin 5 is the ground.

 

[SHCreeper]

9 minutes ago, IkeaGnome said:

Do pins 4 and 6, bottom left and bottom right of the 3x2 connector short to ground? The only thing those two sets of pins have in common, but don't share with pin 5 is the ground.

 

Thank you for your help!  
Yes, both pins short to ground (so 1,3,4,5,6). I also found that the resistor "RS501" which is close to the 3x2 connector shorts to ground (~21 ohms) and the others don't (several k ohms). (If that might be an issue).

[IkeaGnome]

3 minutes ago, SHCreeper said:

Thank you for your help!  
Yes, both pins short to ground (so 1,3,4,5,6). I also found that the resistor "RS501" which is close to the 3x2 connector shorts to ground and the others don't. (If that might be an issue).

rs501 is a 0.005 ohm resistor, but the other power pin is meant to go through it also. If you're comfortable soldering, you could remove that resistor and see if you still get short to ground on pins 4 and 6, and check RS501's resistance. RS1 doesn't short to ground? It's also a 0.005 ohm.

I wouldn't power it up while you're testing this, but a person could remove RS501 and RS1, swap them and make sure it moves the problem to have your pcb lanes short now. Any 5M OHM resistor of that size would work there. 

 

 

[SHCreeper]

21 minutes ago, IkeaGnome said:

rs501 is a 0.005 ohm resistor, but the other power pin is meant to go through it also. If you're comfortable soldering, you could remove that resistor and see if you still get short to ground on pins 4 and 6, and check RS501's resistance. RS1 doesn't short to ground? It's also a 0.005 ohm.

I wouldn't power it up while you're testing this, but a person could remove RS501 and RS1, swap them and make sure it moves the problem to have your pcb lanes short now. Any 5M OHM resistor of that size would work there. 

 

 

 

Okay, thank you for the next steps. My multimeter does not have a low enough resolution to measure these low resistances. The RS1 does not short to ground so I can try that one out. I'll need to brush up on my soldering skills and come back once I have tried it.

[IkeaGnome]

1 minute ago, SHCreeper said:

 

Okay, thank you for the next steps. My multimeter does not have a low enough resolution to measure these low resistances. The RS1 does not short to ground so I can try that one out. I'll need to brush up on my soldering skills and come back once I have tried it.

Depending on your patience, Aliexpress tends to be the cheapest place to get SMDs, but can take for ever to show up and are typically more than you'd want if this is all you're using them for. It's a bit of a pain getting them in less than 50 pieces, but they're cheap.

https://www.aliexpress.us/item/3256801311364361.html?spm=a2g0o.productlist.main.73.30c0KYqoKYqoEp&pdp_ext_f={"sku_id"%3A"12000016355483501"}&pdp_npi=3%40dis!USD!2.98!2.83!!!!!%4021227a0f16789916370906229d071c!12000016355483501!sea!US!4173161901&curPageLogUid=dFOtDaHohnRT

 

If not, you might get lucky finding one at an electrical supply store or on another PCB you don't mind turning into a donor. 

 

[SHCreeper]

On 3/16/2023 at 7:42 PM, IkeaGnome said:

Depending on your patience, Aliexpress tends to be the cheapest place to get SMDs, but can take for ever to show up and are typically more than you'd want if this is all you're using them for. It's a bit of a pain getting them in less than 50 pieces, but they're cheap.

https://www.aliexpress.us/item/3256801311364361.html?spm=a2g0o.productlist.main.73.30c0KYqoKYqoEp&pdp_ext_f={"sku_id"%3A"12000016355483501"}&pdp_npi=3%40dis!USD!2.98!2.83!!!!!%4021227a0f16789916370906229d071c!12000016355483501!sea!US!4173161901&curPageLogUid=dFOtDaHohnRT

 

If not, you might get lucky finding one at an electrical supply store or on another PCB you don't mind turning into a donor. 

 

Alright, I'm back! 

I've switched the two components and still have the same short. It seems like that one was not the issue. Is there anything that this resistor is connected to that might cause the issue?

[IkeaGnome]

3 hours ago, SHCreeper said:

Alright, I'm back! 

I've switched the two components and still have the same short. It seems like that one was not the issue. Is there anything that this resistor is connected to that might cause the issue?

That resistor is part of a very large circuit. Short of having the board in front of me to go through, just start walking down the schematic until you find something else shorting that when you remove it removes the short. Walking someone through step by step for every component in that circuit is going to take a long time and a lot of messages back and forth. 

I'm not against helping, I don't have the board in front of me, so I can't do it on my own.