mosfet shorted gtx 770 !!

[mohsen gtx]

Hi guys , i have msi gtx 770 tf , when i start my pc there is no signal and the fans run at 100% .
When i check it i noticed that the mosfets and the electrolytic capacitors are shorted !!!

And there is no short in the smd caps behind the gpu
Please help me how can i solve this problem

 

[zoltan.boese]

How did you come to the conclusion that the MOSFETs are shorted? What exactly was measured?
Is that your gtx970 on the photo? Does your PC run without gpu having the monitor cable connected to the motherboard?
Have you read this guide http://www.tomshardware.co.uk/forum/261145-31-perform-steps-posting-post-boot-video-problems ?

 

[mohsen gtx]

I read 1.8 ohm between S and D pins!!!The system not detect my gtx 770 !!and this capacitors shorted
https://preview.ibb.co/cszk3z/20180806_145814.jpg



Look dear , i get this problem when i connect 12v dc to the gtx fan connector , in the pwm pin and ground!!

 

[zoltan.boese]

MOSFETs all have a Rds resistance, it plays a role in their ability to amplify signals and there is nothing wrong with it. Rds=1.8Ohm is normal.
Just look at the data sheet of an ordinary transistor: http://www.farnell.com/datasheets/83450.pdf

As for the capacitors. If you measure direct current resistance it will always be zero. They conduct. If you switch alternating current on capacitors, they will need time to be charged after the current changes direction, therefore will have a measurable impedance dependent on the frequency of the current. That is just how they work.

A GPU not being detected can be caused by other problems. Does your PCI slot work with other cards? Have you updated your BIOS lately? Can you simply install the card to another PC to be sure it is the one causing the issue?

 

[zoltan.boese]

Sorry I forgot about the PWM fan connector. I guess that is eighter an output. ASUS cards have such ones. Or the extra connector may be there to override the speed-temeprature curve of the firmware. If you connect 12V, that equals to 100% speed. If you want your fans to run at 40%, give them 5V.
GPU fans are usually supplied by the card´s voltage supply circuits. The 8 pin connectors have enough juice for the card and its fans.

What happens if you do not connect anything to the 4pin fan header?

 

[mohsen gtx]

But i smell a smoke after connecting 12v to the 4 pin connector !!
And i dont know wich components whos burned

 

[zoltan.boese]

I am sorry to read that. Remote assistance is difficult in such cases. And you should not connect the board, if it overheats right away.
Look for any sign of colour change or bulging!
There are usually buck converters (DC to DC voltage regulators) around the connectors. They look like

, but may have different packaging. Those would be a good place to start, but with lover voltage on the connectors, or short intervals of time plugged in.
You may also examine diodes (components with 3 pins or just two) in the same path, they should have a resistance one direction only.

 

[mohsen gtx]

I remove this component
https://preview.ibb.co/hNhuLz/20180817_134646.jpg
I dont know if it is a transistor or diode , i cant read the smd code , and i test it out if the board .
I read 290 in dmm in both pins like this
https://image.ibb.co/fDM4Lz/20180817_134417.png
I also unplug the 4 pin fan connector and the gpu heat up when booting pc , but pc dont detect the gpu !!!