Sign in with
Sign up | Sign in
Your question
Solved

GPU short circuit. EXPERTS PLEASE HELP!!

Tags:
Last response: in Graphics & Displays
Share
August 2, 2013 3:28:40 AM

Hello people, this is my second post about GPU short. MY XFX GTX260 has a short circuit somewhere and I need to test and replace the fault.
So this question will be for the GPU experts.
MY last thread is here if you need some more information.
http://www.tomshardware.com/answers/id-1742631/xfx-gtx2...

August 2, 2013 4:37:05 AM

karan28 said:
Hello people, this is my second post about GPU short. MY XFX GTX260 has a short circuit somewhere and I need to test and replace the fault.
So this question will be for the GPU experts.
MY last thread is here if you need some more information.
http://www.tomshardware.com/answers/id-1742631/xfx-gtx2...


This is power connectors, I assume. You need to see to what cord is connected. If it's connected to black, then is normal to be short circuit to the ground, b'cause black color is for gnd. You need to test your graphic in another rig to see if works there. Is there a warranty any kind for your card? If you disassemble you card then warranty is gone.
m
0
l
August 2, 2013 4:43:53 AM

mironso said:
karan28 said:
Hello people, this is my second post about GPU short. MY XFX GTX260 has a short circuit somewhere and I need to test and replace the fault.
So this question will be for the GPU experts.
MY last thread is here if you need some more information.
http://www.tomshardware.com/answers/id-1742631/xfx-gtx2...


This is power connectors, I assume. You need to see to what cord is connected. If it's connected to black, then is normal to be short circuit to the ground, b'cause black color is for gnd. You need to test your graphic in another rig to see if works there. Is there a warranty any kind for your card? If you disassemble you card then warranty is gone.

It is out of warranty. I went to the service centre but they dont do repairs.
So I have to try it myself.
And about your assumption, There is no problem with power connectors from the PSU. But there is with the connectors in the card. All of them are shorted to the ground.
And there's no use of testing the card in other pc because as soon as i plug the power connector to the card (TESTEd with 2 PSU's), the system doesnt run. Fans just move for a sec and then stop to prevent the short.
So its the card for sure.
m
0
l
Related resources
August 2, 2013 4:57:21 AM

In last thread, you circled just two pins. Now you saying that all pins are shorted to gnd. Put pisture from another side of card. Try checking your capacitors, resistors. Find voltage regulators, may be they are dead.
m
0
l
August 2, 2013 5:18:40 AM

mironso said:
In last thread, you circled just two pins. Now you saying that all pins are shorted to gnd. Put pisture from another side of card. Try checking your capacitors, resistors. Find voltage regulators, may be they are dead.

No . I said except the circled pins, all others are shorted.





I know what components are resistors, capacitors, but not regulators. And how do i test them ?
I have multimeter and soldering iron. I know how to solder bigger components.
In the 4th pic. I tried to clean the area where i have circled in red. I was kind of rusty. But I dont know what exactly was the material on top of that. But i dont think it caused the problem because it was already on it when i had bought the card from someone.
m
0
l

Best solution

August 2, 2013 5:55:33 AM

Ok, sorry for misunderstanding.
On first picture, you can see power pins and row of capacitors 820u - 2v5. All this part is power circuitry for your card. You need to find markings on these chips, google it to see what they are. On data sheet you'll find pin out. Basically it's in, out and gnd. With multimeter you will test it for short circuit.
Share
August 2, 2013 10:10:34 AM

Thank you mironso for the help. I'll see and revert back to you.
m
0
l
August 9, 2013 9:40:38 AM

So I kind of fixed it.
There was a bad MOSFET which caused the short. Mironso helped me in testing it. I removed it and the short was gone.
I had that replaced but unfortunately while disassembling, I damaged a capacitor. Which I wasn't able to get because I dont have something to test for the capacitance.
So, I guess because of that capacitor, The fan control circuit is not working. Due to which The Fan does not move but GPU works.
I removed the 2 out of 4 wires from the fan connector. The yellow(12V) and black (GND) wires are connected and fan is running at full speed now.
I have tested it for 2 hours while playing different games. It works well.
I replaced the thermal paste, the temperature stays at 65 deg C under load.
Thanks again mironso for your time and helpful knowledge.
:-)
I hope this helps someone.
m
0
l
April 28, 2014 1:47:48 PM

Hi, how did you go about finding and replacing the MOSFET, I too have the problem you encountered with the 6 pin power connector, but I am very unclear how I would find the MOSFET on my GTX 660.



karan28 said:
So I kind of fixed it.
There was a bad MOSFET which caused the short. Mironso helped me in testing it. I removed it and the short was gone.
I had that replaced but unfortunately while disassembling, I damaged a capacitor. Which I wasn't able to get because I dont have something to test for the capacitance.
So, I guess because of that capacitor, The fan control circuit is not working. Due to which The Fan does not move but GPU works.
I removed the 2 out of 4 wires from the fan connector. The yellow(12V) and black (GND) wires are connected and fan is running at full speed now.
I have tested it for 2 hours while playing different games. It works well.
I replaced the thermal paste, the temperature stays at 65 deg C under load.
Thanks again mironso for your time and helpful knowledge.
:-)
I hope this helps someone.


m
0
l
August 5, 2014 10:33:26 PM

Can some of you tell how did you find that bad mosfet? I have the same issue with my 780 ti matrix. While watching a video on youtube the system shutdown and now it wont power on with that card installed, works with other cards.
m
0
l
August 6, 2014 12:24:18 AM

for people asking about the MOSFET.
Check this photo.
http://i.imgur.com/w8tEgwC.jpg
Circled in red.
The 2 side terminals were shorted so removing that fixed my problem.
m
0
l
August 6, 2014 2:50:40 PM

My 780 ti matrix will prevent system to power on if the right 8 pin power connector is plugged. Any experts here that could advice how to possbily troubleshoot and find a short component? I can't see physical damage on card, I've cleaned it pc works well with other cards like 7970 and other 780 ti. This happened for no reason while I was watching a video on youtube and system just shutdown and it will no more run.

The pcb is very complex, that is why it's very hard to troubleshoot components.
m
0
l
August 6, 2014 2:59:19 PM

I would check the VRM mosfets for gate-source shorts
m
0
l
August 6, 2014 5:27:44 PM

Can a small onboard brown cap cause a short like that? I found one that does not give any resistance value accross it. The shorted 8 pin beeps to one side of it, the other 8 pin gives 40 ohm value to the side the shorted one beeps.

http://i.imgur.com/cUKKfSc.jpg
m
0
l
August 6, 2014 6:02:19 PM

Small capacitors should not show any resistance across them.
m
0
l
August 7, 2014 4:16:07 AM

Well I don't know what that component is or the others around it. It actually shows 120kohm value.
m
0
l
August 7, 2014 6:21:24 AM

Hey could someone explain something to me a bit. In this picture: http://i.imgur.com/gHaKrBu.jpg
The circled brown components ( I don't know if they are caps) beep accross them and give like 1-2 ohm value, same what I get from the right connector's 12v pins to ground and gpu hotwire hole. Need to remember that the right connector is preventing the system from turning on.

The ones on the left so under the left connector that look identical do not beep and give like 500 and 600 ohm values. Could this be something?
m
0
l
August 7, 2014 6:40:40 AM

Those are small ceramic capacitors. But most likely the problem is elsewhere and they are just in parallel with the fault.
Bypass and filtering caps across the input power are very common

A shorted mosfet is more likely
m
0
l
August 7, 2014 7:36:09 AM

I can see a gash in that mosfet either from burning/heating or physical damage. There is a very good chance that is the problem
m
0
l
August 7, 2014 8:08:03 AM

Ye it is it, does not give values like the other one next to it. Could you explain me what the markings on the mosfet means. I think I need one there to run the card, right?

here: http://i.imgur.com/0r6rCAu.jpg

It has big M logo
B20
P03
CFL0325
m
0
l
August 9, 2014 4:38:01 PM

Can anyone say if that component is even needed to run the card? Is just basic a mosfet or something very particular?
m
0
l
!