Gtx 970 strange problem

[ss45]

Hi I have this gtx 970

If I plug power to pin 1(left) the gpu will not be detected.
Basically no gpu vcore, ram voltage, etc.


If I only plug number 2, vcore voltage, ram voltage all appears normally, gpu itself will appear on device manager, but of course since not both are plugged, it shows error 43

I have checked line number 1, no short at all... Which confuses me.
But when only line 1 connected, gpu vcore will read 0.07 volt

Both line 1 and 2 connected shows the same symptom..
So it has sth to do with line 1

If anyone has suggestion please let me know. Thanks

[dicky96]

Re: Gtx 970 strange problem

It is not unusual for the two EATX12V connectors to power different phases or different VRMs

And also I have seen some models of GPU (GTX 6x0 for example) where the Vcore VRM is powered from EATX12V and the Vram VRM is powered from the PCIe 12V.

What happens when you plug both connectors?

[ss45]

Re: Gtx 970 strange problem

It is not unusual for the two EATX12V connectors to power different phases or different VRMs
-> I agree with that

(Pcie 12v only) -> normal gpu vcore, ram voltage, pcie 1.0v rail ,5v , 3.3v
Gpu gets detected in device manager, but shows error 43

(Pcie 12 + external power 1) -> no gpu vcore no ram voltage
Gpu not detected in device manager.

(Pcie 12 + ext pwr 2) -> same as (pcie 12) only

(Pcie 12 + ext 1 + ext 2) -> same as (pcie 12 + ext 1)

Checked all rail pcie 12, ext 1, ext 2, normal no short

5v, 3.3v, pciex 1.0v normal resistance

[dicky96]

Re: Gtx 970 strange problem

It sounds like there could be some device or circuit used as a logical AND gate that is supposed to detect the various supply voltages are present and allow the GPU to power up - but for some reason it is giving the wrong signal? Maybe due to missing or faulty SMD resistors in that circuit.

That is a bit of an inspired guess though.

What is the history of this GPU, do you know?

[ss45]

Re: Gtx 970 strange problem

thank you for your reply.

It sounds like there could be some device or circuit used as a logical AND gate that is supposed to detect the various supply voltages are present and allow the GPU to power up - but for some reason it is giving the wrong signal? Maybe due to missing or faulty SMD resistors in that circuit.

That is a bit of an inspired guess though.

-well thats unfortunate. with no schematic its a nightmare to do the tracing. i wish i had that much free time

What is the history of this GPU, do you know?
- it was working fine until few weeks ago