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GTX 670 reference PCB - voltmod - Page 7

post #61 of 94
Thread Starter 
Well, I don't know what happened when the VFB pin failed.. It shouldn't break the card since OVP is still there..

But I guess if I had shorted the card, there would be black dust biggrin.gif
post #62 of 94
Quote:
Originally Posted by Olper View Post

Well, I don't know what happened when the VFB pin failed.. It shouldn't break the card since OVP is still there..
But I guess if I had shorted the card, there would be black dust biggrin.gif
Quick OT: Could you do me a favor and measure point C594 on the backside please?

Here's my issue: http://www.overclock.net/t/1334870/how-to-vmod-a-660-ti/0_50#post_18784792
post #63 of 94
Thread Starter 
I can measure... but measure what? Capacitance? Resistance to GND?
Gotta go sleep now, but I'll do it tomorrow =)
post #64 of 94
Quote:
Originally Posted by Olper View Post

I can measure... but measure what? Capacitance? Resistance to GND?
Gotta go sleep now, but I'll do it tomorrow =)
Please measure the resistance of both ends for me please...
post #65 of 94
Thread Starter 
resistance over the capacitor is 650ohms.

just for reference, resistance over C600 reads 76ohms. Mine has different slots populated though. For example, I have C607 and C625 populated unlike in this pic: http://cdn.overclock.net/5/5c/5cfe4ab6_1160244.jpeg


By the way, I think I know what went wrong. I think my mosfets are fried.

I took the waterblock off the card when I mod the 5mohm shunts. The thermal pads on mosfets had been squeezed once. They might not have gotten as good contact the second time. Then they would get hot when I loaded the card.. I got a few black screens with GPUv sinking 0V... What the hell, I thought and fired the system back on... xD


I can't identify the mosfets. Well, I think it's an IC with two mosfets and a controller, but still..
Markings on the component: first there is the letter f. It looks like a logo.. Fairchild's logo.. then follows:

DC13XX
FDMF
6823C


Edit:

wasn't that hard...
http://www.fairchildsemi.com/pf/FD/FDMF6823C.html
http://www.fairchildsemi.com/ds/FD/FDMF6823C.pdf

I bet you could change to FDMF6823A.. It's a bit more expensive as it has a larger chip, but it can tolerate about 20% more current..
Edited by Olper - 12/13/12 at 8:58am
post #66 of 94
Those types of mosfets will be hard to replace. Really need a reflow machine. Even then, you'll need the hand of a surgeon.
    
CPUMotherboardGraphicsRAM
E8400, E8600, 980BE T2RS+, P5E3, TA890FXE 8800GTS's,GTX's,GS,Ultra's,9600GT Lots of D9's and some crap DDR3 
Hard DrivePowerCase
Seagate 250GB + 80GB WD for benching TT 875w, Corsair 650TX Custom bench station 
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CPUMotherboardGraphicsRAM
E8400, E8600, 980BE T2RS+, P5E3, TA890FXE 8800GTS's,GTX's,GS,Ultra's,9600GT Lots of D9's and some crap DDR3 
Hard DrivePowerCase
Seagate 250GB + 80GB WD for benching TT 875w, Corsair 650TX Custom bench station 
  hide details  
Reply
post #67 of 94
Or of a watchmaker biggrin.gif
post #68 of 94

SMD station with hot-air..  I dont have one.. but would love to use one sometime biggrin.gif

post #69 of 94
Hmmmm, wonder how well a toaster oven would work....
    
CPUMotherboardGraphicsRAM
E8400, E8600, 980BE T2RS+, P5E3, TA890FXE 8800GTS's,GTX's,GS,Ultra's,9600GT Lots of D9's and some crap DDR3 
Hard DrivePowerCase
Seagate 250GB + 80GB WD for benching TT 875w, Corsair 650TX Custom bench station 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
E8400, E8600, 980BE T2RS+, P5E3, TA890FXE 8800GTS's,GTX's,GS,Ultra's,9600GT Lots of D9's and some crap DDR3 
Hard DrivePowerCase
Seagate 250GB + 80GB WD for benching TT 875w, Corsair 650TX Custom bench station 
  hide details  
Reply
post #70 of 94
Thread Starter 
I'm aware of the difficulty. Hot air alone is risky, because there is so many other components nearby. The airflow will easily blow away small components biggrin.gif
Good thing I have hot air and and extractor tools(link) at work. The smallest we have is 10x10mm, while these componets are 6x6mm.. If there is components nearby, I'll have to remove those before.

I just hope my diagnostics is right though. I don't know how "mosfets" like this behave when broken. It's not really a mosfet, because it has so much control circuits inside. I actually holds two mosfets inside.. Mosfets typically break so that all pins short circuit, but of these I don't know.
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