How to Vmods Vdimm ABIT KN9

[cecico135]

It's 2.3V vdimm
PLs tell me mod for 2.5V volt memory?
thanks!

[aasmaukr]

Hey, can you tell me the markings on the chip I've circled in red on the pic I attached?

If it is a W83320G, can you measure resistance between ground and pin 8 of the chip?

Edit: I believe it is a W83320G. I've marked pin 8 in red on this pic: http://home.no/aasmaukr/image.jpg


The vdimm mod for your board should be soldering a VR between pin 8 of the chip and ground. A general rule to figure out what ohm value your VR needs to be, multiply the resistance between ground and pin 8 by 20.
I.E. if the resistance is 2kohm you need a 40kohm VR (or 50kohm will do too, but preferably not any lower than 40kohm).

[cecico135]

Hey, can you tell me the markings on the chip I've circled in red on the pic I attached?

If it is a W83320G, can you measure resistance between ground and pin 8 of the chip?

Edit: I believe it is a W83320G. I've marked pin 8 in red on this pic:


The vdimm mod for your board should be soldering a VR between pin 8 of the chip and ground. To find out what value your VR needs to be, multiply the resistance between ground and pin 8 by 20.
I.E. if the resistance is 2kohm you need a 40kohm VR (or 50kohm will do too, but not any lower than 40kohm).

Yeah!
that's Winbond's chip W83320G / 26147170-ZY / 627GB

Thank you for help me!

[aasmaukr]

Okay, no problem Do you have a digital multimeter so you can measure the resistance between ground and pin 8 of the chip?

[cecico135]

Okay, no problem Do you have a digital multimeter so you can measure the resistance between ground and pin 8 of the chip?

OK!

multiply the resistance between ground and pin 8 by 20.
I.E. if the resistance is 2kohm you need a 40kohm VR (or 50kohm will do too, but preferably not any lower than 40kohm).

Where's 20?

[aasmaukr]

If the original resistance between pin 8 and ground is 4,5kohm you need a potentiometer(VR) with a much higher value than 4,5kohm to do the mod, because connecting resistors in paralell makes the resistance lower. That's why we usually multiply with 20.
You can use this formula to calculate the new resistance when connecting resistors in paralell: R=(R1*R2)/(R1+R2)
So if you connect a 100kohm VR in paralell with the 4,5kohm resistance between ground and pin 8 of the regulator chip you get: R=(4,5kohm*100kohm)/(4,5kohm+100kohm)=~4,3kohm. As you see, not a huge difference. If you used a 50kohm VR instead of the 100kohm you would get 4,12kohm, which would work too, but you woud get a higher voltage at the lowest setting.


You've circled the VR/potentiometer that I use to control vdimm on that pic.

This mod should work for your board:

Connect 100k VR between ground and pin 8 of the W83320G. You might have to turn the VR many times before the vdimm starts increasing, so be careful and watch the voltage.

[cecico135]

If the original resistance between pin 8 and ground is 4,5kohm you need a potentiometer(VR) with a much higher value than 4,5kohm to do the mod, because connecting resistors in paralell makes the resistance lower. That's why we usually multiply with 20.
You can use this formula to calculate the new resistance when connecting resistors in paralell: R=(R1*R2)/(R1+R2)
So if you connect a 100kohm VR in paralell with the 4,5kohm resistance between ground and pin 8 of the regulator chip you get: R=(4,5kohm*100kohm)/(4,5kohm+100kohm)=~4,3kohm. As you see, not a huge difference. If you used a 50kohm VR instead of the 100kohm you would get 4,12kohm, which would work too, but you woud get a higher voltage at the lowest setting.


You've circled the VR/potentiometer that I use to control vdimm on that pic.

This mod should work for your board:

Connect 100k VR between ground and pin 8 of the W8802G. You might have to turn the VR many times before the vdimm starts increasing, so be careful and watch the voltage.

Thanks you very much!

[DaRoN]

Hi.
Huh, I've discovered this mod with identical method
But I have some troubles with it. I've used the same values of VR, I've soldered VR(100kOhm) between ground and pin 8 of Winbond controller, and this is the point. With decreasing the resistance, voltage for my memories decreases too How it is possible?

Every mod i've done was working fine with this method. Decreasing the resistance is increasing the voltage!. But on this mobo is different!
Why?

Can you give me a tip what i've done wrong?
BTW - now i'll try the 200kOhm VR, set on 100kOhm. We'll se what results it give.

[aasmaukr]

That's really weird, I'm sorry but I don't know why that would happen .


It might work to disconnect the FB pin from the board (lift it up by desoldering it) and attaching a VR with a bit higher value than the original resistance between pin 8 and ground. Then set the VR to original resistance between ground and FB pin and tune for higher resistance for higher voltage.

I.e. if the original resistance is 7kohm, use a 10kohm VR, start at 7kohm resistance and take the resistance higher for more voltage I suppose that would work, but you might want to wait for someone else to confirm that's the way to do it.

Could you measure the resistance between the FB pin and ground with the mod disconnected?

[DaRoN]

With the mod disconnected is 5.10kOhm.

I've tried now the 200kOhm resistance. This gave nothing to me.
I'm worring about desoldering the 8pin, beacause with my trafo solder ( ) i can put my mobo down ;]

OK - problem is resolved. My forums friend MaSell told me that i would try to resolder ground. And it resolve my bug
AnyWay - thanks for help aasmaukr. The ATX24 ground suxx

[cecico135]

With the mod disconnected is 5.10kOhm.

I've tried now the 200kOhm resistance. This gave nothing to me.
I'm worring about desoldering the 8pin, beacause with my trafo solder ( ) i can put my mobo down ;]

OK - problem is resolved. My forums friend MaSell told me that i would try to resolder ground. And it resolve my bug
AnyWay - thanks for help aasmaukr. The ATX24 ground suxx