# ECS nForce4-A939 Voltmods



## celemine1Gig (May 10, 2006)

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## SuperStarr (Jun 10, 2007)

Many greetings! I need help about ISL6566.
I still can't crack it at all! 

Need to know how to find i.e. how to be sure I am find VID pins?
What to measure?

I post 2 pics bellow, one (green PCB) is Biostar NF4UL-A9A and second (blue PCB) is GA-K8NS-9-RH.
Both have ISL6566 as CPU PWM so i can with feedback vcore mod to gain only 0.15V.
Problem more for GA is that MoBo don't react on BIOS set V more than 1.425 so with current vcore, max V it can gain is 1.425V + 0.15V. I need, if it can be (simply) maked to gain 1.55V + 0.15V.
On Biostar MoBo, situation is little better, currently I can gain 1.525V (real) + 0.15V. Finally about 1.65V which is enough for Venice's.

If you can help me how to get 1.55V as default on both MoBo's I will be very grateful.

Is on Biostar model, is RN8 place for VID's, if it is, where is fifth VID?

Second quest is:
How to find resistors for vdroop?


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## celemine1Gig (Jun 10, 2007)

All you need to do to find the vid pin-connections, is to use a digital mutlimeter and set it to continuity test mode (test for a resistance close to zero, i.e. direct connections). Then you let one probe touch the known vid pin on the isl6566 controller and probe around for points directly connected to it on the board in that area. Or sometimes you can even follow the traces on the mobo, just by visual inspection.
Just repeat the process until you have found all 5 vid-pin connections. 

BTW, the controller can supply far more voltage in VRM9 mode, but that modification would most likely need more time. AND, ~1.7V should be more than enough for todays CPUs.


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## SuperStarr (Jun 10, 2007)

OK, i will find it (direct connections).
If I manage right, when found VID's only have to do is short-pin him (never mind which, I understund table  ) to GND? If I have luck it will be near searched pin (just like on Yosur ECS or some ASRock MoBo's)?
But, what if some of that has resistor or capacitor connected?
Can it be?


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## Dippyskoodlez (Jun 10, 2007)

Someone may find this useful!

(Pictures are pretty)
Very nice work.

edit: lol, i need to L2read. You are using a dip switch!

Wonder what other mobos use this for voltage control..


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## celemine1Gig (Jun 11, 2007)

BTW, Superstarr, you just told me that you were confused that you couldn't find pull-up voltage points on your boards. 
Pull up means that you just need a higher voltage than the reference point, to make the signal appear as a digital 1, i.e. high. Or lower than the reference for a digital 0 (low), as pull-down voltage. If I remember correctly, 1.2V was the reference point for the ISL6566. That means that you could use for example 3.3V (directly from the NT as pull up and ground as pull down. 

Ahh, and another little update: There is an easier VDroop mod.  Just didn't find it back then when I wrote the article.


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## d44ve (Jun 11, 2007)

screw that.... I couldnt solder that damn good


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## SuperStarr (Jun 11, 2007)

celemine1Gig said:


> BTW, Superstarr, you just told me that you were confused that you couldn't find pull-up voltage points on your boards.
> Pull up means that you just need a higher voltage than the reference point, to make the signal appear as a digital 1, i.e. high. Or lower than the reference for a digital 0 (low), as pull-down voltage. If I remember correctly, 1.2V was the reference point for the ISL6566. That means that you could use for example 3.3V (directly from the NT as pull up and ground as pull down.
> 
> Ahh, and another little update: There is an easier VDroop mod.  Just didn't find it back then when I wrote the article.



OK, i Understund. If I want to Pull-Down I must solder to GND or if I want to Pull-Up I must solder it to "NT".
But, what is NT and how I can find it if it's not around VID point as on Your ECS or ARSock like I have before (see attach).
It was 5 VID points and 5 Pull-Up points in same square.
On current MoBo's (see post 2) isn't that situation. Where to search for Pull-Up points and how find it with multimer?


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## Solaris17 (Jun 11, 2007)

sweet i have this board in another rig and was wondering how to adjust the vcore past a measly.2


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## celemine1Gig (Jun 11, 2007)

SuperStarr said:


> OK, i Understund. If I want to Pull-Down I must solder to GND or if I want to Pull-Up I must solder it to "NT".
> But, what is NT and how I can find it if it's not around VID point as on Your ECS or ARSock like I have before (see attach).
> It was 5 VID points and 5 Pull-Up points in same square.
> On current MoBo's (see post 2) isn't that situation. Where to search for Pull-Up points and how find it with multimer?



Ooops, I'm sorry. posted on german forums at the same time NT=Netzteil=Power Supply=PSU 
3.3V directly from the PSU.


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## SuperStarr (Jun 16, 2007)

Can this VID (ISL6566) mod be worked on Processor?
Look atachment (pic):


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## celemine1Gig (Jun 30, 2007)

SuperStarr said:


> Can this VID (ISL6566) mod be worked on Processor?
> Look atachment (pic):



Sorry for the late reply. Was very busy the last weeks. 

On topic: Of course this would work. You mod the CPU and not the board. And the VCore range is the one specified by AMD, so all motherboards should support it.


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## SuperStarr (Jun 30, 2007)

Thanks again!
This is "sufficient" mod (1.55V + 10-15% with feedback mod) for Venice's.
If I do it, I will post pics. I plain to do that with liquid silver.
Best regards!


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