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Author Topic: Where are the PWM controllers for the VRMs on this graphic card?  (Read 1933 times)

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Offline TheGenesisTopic starter

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Where are the PWM controllers for the VRMs on this graphic card?
« on: November 05, 2018, 09:42:01 pm »
Please, someone help me to find the controller for the GPU and the RAMs.

By just guessing i would say the controller for the GPU is the "ON NCP4205" on that little daughterboard on the left ... right?

And is this thing controlling all the 6 phases (coils and drMOS's) in the middle?

But where are the VRMs for the VRAM?

Thanks in advance.
Thom

« Last Edit: November 05, 2018, 11:50:54 pm by TheGenesis »
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Offline aheid

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Re: Where are the PWM controllers for the VRMs on this graphic card?
« Reply #1 on: November 05, 2018, 10:03:06 pm »
I'm gonna go out on a limb and say there probably are no psychics or anyone with a crystal ball here...

Did you forget to attach some pictures or some links?
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Offline TheGenesisTopic starter

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Re: Where are the PWM controllers for the VRMs on this graphic card?
« Reply #2 on: November 05, 2018, 11:51:53 pm »
Sorry ... and now with the pic :)
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Offline T3sl4co1l

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Re: Where are the PWM controllers for the VRMs on this graphic card?
« Reply #3 on: November 06, 2018, 04:34:13 am »
Yes, NCP4206 is probably the controller, which is going to be VCORE I guess (1.1V or thereabouts)?

IO supply is probably U14, whatever it is. I don't recognize the code, and there's no MFG mark... could be anyone...

Tim
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Offline radioFlash

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Re: Where are the PWM controllers for the VRMs on this graphic card?
« Reply #4 on: November 08, 2018, 01:59:09 am »
There are six large inductors sitting next to chips marked SIC780: "The SiC780 is an integrated power stage solution optimized for synchronous buck applications..."

https://www.vishay.com/docs/63788/sic780.pdf
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Offline Chris_S

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Re: Where are the PWM controllers for the VRMs on this graphic card?
« Reply #5 on: November 08, 2018, 03:31:00 am »
The 2 small phases between the large inductors are your VRAM VRM.

So the 2 R33 inductors, 4901NF Mosfets, and the surrounding components. The actual controller should be right below the r2r cap.



You are correct about the other phases for the actual GPU.
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Offline TheGenesisTopic starter

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Re: Where are the PWM controllers for the VRMs on this graphic card?
« Reply #6 on: November 08, 2018, 08:36:58 am »
Ok ... thanks.

I have already fearedif the little ic marked "OT=FF -H2B" would be the controller ... i couldn't find any information of that piece.

Mhmm ... three of the GPU Mosfets are shorted.

Can someone tell me, what should I expect, when measuring the resistance of the inductors?
My Multimeter shows open-line on everyone. Is it possible that my Multimeter is not accurate enough?
« Last Edit: November 09, 2018, 08:54:18 pm by TheGenesis »
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