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MONKEYMAN 15th December, 2005 12:10 PM

Vdimm/Vcore reference points.
3 Attachment(s)
Can anyone with some electronics know-how point out where I would measure the Vdimm and Vcore on this card?
Its a weird one for sure, based on the NV40 core(according to Rivatuner), or the NV45 according to spec sheets online. The fact the pipelines can be unlocked say to me NV40 though, it has the 6800NU pci-e reference heatsink but with the voltage regulation heatsink of the 6800Ultra, also it appears based on a version of the 6800Ulra pci-e reference board.
So its a 6800NU/Ultra sorta.....I think..... :confused:
At the moment it clocks to the same speed as the 6800ultra upto 400/1100 or 425/1000 and the 6th vertex shader is unlocked 100% ok but the last pixel-pipe quad seems quite iffy.
I would like to do a pencil mod to bump up the voltages just a touch, also I would like to see what they are as standard.
Any help appreciated.

-apologize for pic quality :rolleyes:

MONKEYMAN 15th December, 2005 12:24 PM

2 Attachment(s)
Right found the points to measure Vcore is about 1.33v and Vddr is about 2.03v.
Can I just pencil the resistors at the measuring points or do I need to use another point?

Gizmo 15th December, 2005 02:13 PM

The points you've hilighted on the board for measuring are actually capacitors, not resistors. Penciling them would do no good and might actually cause the board to function worse.

Without being able to look at the board or get clearer pictures, I can only make some guesses about what you need to do.

I <THINK> that the multi-legged "caterpillar" on the bottom right of the back side of the board is your voltage regulator for the vCore. The voltage divider for feedback will most likely be in that area somewhere.

I <THINK> the large three legged transistor directly above the "caterpillar" is probably the FET for vDimm regulator. Most likely it is controlled by something like an LM339 Op-Amp, although I can't see it in any of the pictures. Then again, that might be for something else, or might not be a FET at all.

The front of the board appears to have 4 inductors, so it might be using a switching-mode regulator for both vCore and vDimm, with 3-phase for the core and 1-phase for the memory.

I just don't have enough to work with. Sorry. :(

MONKEYMAN 15th December, 2005 02:37 PM

Ill get more info and post back, I should have given more to go on, thanks for your input. :thumbsup:

MONKEYMAN 15th December, 2005 04:30 PM

2 Attachment(s)
Here is a bit of extra detail on the card, I think ive got the Vcore pencil position sorted now but I could do with confirmation of the site for the Vddr penciling so any input you have would be great.

The Vcore resistor to be penciled is about 8Kohm and Vcore is currently 1.33v can someone advise me as to what resistance I should aim for and what is the max Vcore I should take it to, cooling is the stock cooler but I have the fan at 100% and currently the card only just hits 77c max at 400/1100, Ideally I would like to get the core stable at 425+ and memory at 1100+ at the moment I can have one or the other (425/1000 or 400/1100).

Aedan 15th December, 2005 06:07 PM

The ISL6534 is a versatile triple regulator that has two independent synchronous-rectified buck controllers with integrated 12V gate drivers (OUT1 and OUT2) and a linear controller (OUT3) to offer precision regulation of up to three voltage rails. An optional shunt regulator allows 12V only operation, when a 5V supply is not available.

That makes it a voltage regulator, and one designed for fairly high currents.

Aedan 15th December, 2005 06:14 PM

The VT1103M is also a voltage regulator too, so the two are obviously supplying different power lines. Not sure which is which however.

Gizmo 15th December, 2005 06:19 PM

Hmmm.........curiouser and curiouser.

The top chip appears to be a multi-phase switch-mode voltage regulator made by an outfit called Voltera. I'm trying to get some data on it right now, but they are being snooty. I'd guess that it is the regulator for the vCore.

The other chip is a dual single-phase switch-mode plus single linear voltage regulator made by InterSil. Pins 1, 4, and 12 provide the regulator feedback and should be at whatever the output voltage is supposed to be. Since one of the recommended applications for this bad boy is as a voltage regulator for DDR memory, it is probably responsible for vDimm. Do you have a volt meter?

Gizmo 15th December, 2005 06:20 PM


Áedán and I cross posted. :rolling:

MONKEYMAN 15th December, 2005 06:22 PM

The present core voltage is 1.33v, and the resistance of the component is about 8Kohm what would I need to make the resistance to get 1.4v? (I didnt turn up to many electronics classes) :rolling:

MONKEYMAN 15th December, 2005 06:23 PM

yes I got a multimeter handy.

Gizmo 15th December, 2005 06:39 PM

Check the voltages at the pins that I mentioned above. Also, is there any way you can get me a clearer pic of the area of the board with the SIL chip? Maybe get a little further away from it? (dunno if that will help or not, but most digital cameras can't focus any closer than about 3 feet.)

MONKEYMAN 15th December, 2005 06:42 PM

pins numbered like this?


Also do you mean the ISL chip or the SIL chip(silicon images)

Gizmo 15th December, 2005 06:43 PM


Originally Posted by MONKEYMAN
The present core voltage is 1.33v, and the resistance of the component is about 8Kohm what would I need to make the resistance to get 1.4v? (I didnt turn up to many electronics classes) :rolling:

Without knowing how the complete circuit is arranged, I can't tell you. You could try the pencil mod a little at a time until the voltage comes down to where you want, and then see what the resistance is. Or you could put a 100K pot in parallel with it, or put a 50K pot from one side to ground.

MONKEYMAN 15th December, 2005 06:47 PM

1 Attachment(s)
Best my camera will do I'm afraid :(

Im not sure how the pins are numbered on the VT1103M chip

Gizmo 15th December, 2005 06:57 PM


Originally Posted by MONKEYMAN
Best my camera will do I'm afraid :(

Im not sure how the pins are numbered on the VT1103M chip

I'm not interested in the VT1103M right now, as I don't have any data on it. The pins I gave you were for the ISL6534.

The indented circular mark at the corner of the chip indicates the location of pin 1. The pins run straight down that side in order, 1-12. 13 is directly opposite from 12, and then 13-24 run back up the other side, with 24 being directly opposite pin 1.

MONKEYMAN 15th December, 2005 07:31 PM


Pin 1 is at 0.6v,
Pin 4 should not be shorted against pin 5 as it erases the boot sector on your hard disk and use of FIXBOOT is required :rolling:

Im gonna check the other voltages when I have the system out of the case tomorrow and can get the probes on the contacts correctly to the chip(the cpu is blocking access to the card). Im up for modding the card not wiping it out lol.

Gizmo 15th December, 2005 11:19 PM

Volterra are being buttheads:

"In reviewing your request for access for Volterra's secure website, we have discovered that we do not have a current non-disclosure agreement (NDA) in place with your company."

What, I've got to fill out a freaking NDA before I can even find out if your component will do the job I need? Sorry, not today. I'll go with InterSil, or National Semi, or Maxim-Dallas, or Micrel, or SGS-Thomson, or Analog Devices, just to name a few. I can pull THEIR data sheets right off their web site, no questions asked.

How some companies manage to stay in business is quite beyond my comprehension.

MONKEYMAN 16th December, 2005 03:03 AM

Obviously covering up a high-tech conspiracy :rolleyes: , seriously though Ive just been to their site and you have to sign you life away before you could use them.

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