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Msi K7d Master Dual Amd Vdimm Mod

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Ace-a-Rue

Member
Joined
Oct 22, 2001
Location
FL, USA
WARNING....TRY AT YOUR OWN RISK. DOING THIS MOD VOIDS ALL WARRANTIES!

Ok guys, I found how to increase Vdimm beyond 2.5V. Finally got the courage to explore this system owned and operated by "She who must be obeyed"!:D hehehehe

I think everyone knows the 'how to' for the Vcore, which quite honestly will take care of most people's needs. But if you think things aren't stable enough, then this mod will make this duallie m/b work flawlessly. Of course, it doesn't hurt to have very good memory. I am now using a single 512 mb stick of TwinMos Non-ECC, unbuffered.


PARTS NEEDED
PARTS%20NEEDED.jpg



VDIMM MOD
I used a 47K Radio Shack pot with a SMD grabber. I attached the grabber to the 2nd leg on the same side that the AGP slot is on. The picture (below) shows the proximity of the regulator to the DIMM slots and 2 small Mosfets, and the 12V Intel plug. Then just south of the 12V plug is the AGP card. Yup, the VC card is only 32mb so it is not a monster card.

You will solder your 22 or 24 gauge multi-strand wire to the SMD grabber. The other end of this wire will be soldered to the middle lug of the 47K pot. Depending on what direction you want to turn the pot to decrease resistance (this will increase Vdimm) will determine which outer lug you will use to solder the ground wire. It is best to check the resistance first and then set it to the maximum resistance. WARNING, REMEMBER WHICH DIRECTION INCREASES RESISTANCE (reduces voltage), IN FACT, DIAGRAM IT ON PAPER SO YOU DON'T FORGET!

After soldering your ground wire to either outer lug, it will determine which way you set the resistance to maximum. On the other end of the ground wire, attach an electrical grommet that allows you to insert a fastener to ground to the case or motherboard.

To attach the SMD grabber to the 2nd leg/pin, you will push on the SMD plunger head to extend two very tiny claw type copper feet. You just extend it enough to slide the two claw feet around leg/pin 2 and then release the SMD plunger head slowly so it can grasp on to the leg/pin. The approach to the pin should be around 45 degree angle. Coming straight down or straight in horizontally will make it harder to grasp.

k7d_Regulator.jpg



MEASURING VDIMM
You can do this from the bios but I found the accuracy of the reading in doubt so I went to the 2nd Mosfet (pic below) and measured the leg closest to the green capacitor. My reading showed the bios reading low by as much as minus .08V. But, you have to be careful here not to slip with the probe and short out the regulator. Most times when that happens it is for a split second; you just lose the video. One thing you could do to avoid shorting out the Mosfet is to use a single wire attached to a SMD grabber. Attach the grabber to that Mosfet leg and then use electrical tape or cap the end of the wire when not setting/measuring the voltage.

k7d_mosfet.jpg


EDIT: When you are ready to lower the resistance of the pot, turn it very, very slowly. If you turn it to fast, you could lose the video momentarily. Usually a reset or power off/on will correct it.


MY OTHER VMODS
IWILL P4R533-N VCORE & VRIMM MODs

ASUS P4T533 VRIMM MODhttp://www.thenakedreview.com/index.php?p=showarticle&id=82&showpage=3
 
OP
Ace-a-Rue

Ace-a-Rue

Member
Joined
Oct 22, 2001
Location
FL, USA
That is a pic from my last 'how to' which needed a 10K pot becasue the Vrimm mod worked better with a 10K instead of a 47K. This board might possibly use a 10K instead of a 47K. I had to turn the pot some distance (lowering the resistance) before the voltage started to rise. I am going to have to detach the SMD grabber and readout the resistance to see where it is at for 2.7V now for my Vdimm.

I am thinking that a 10K pot in place of the 47K pot will give you about 2.7V Vdimm before adjusting the pot.
 

Audioaficionado

Sparkomatic Moderator
Joined
Apr 29, 2002
2.7v should be a good default starting point with little risk.

BTW this was a great post Ace.

Thanx
 
OP
Ace-a-Rue

Ace-a-Rue

Member
Joined
Oct 22, 2001
Location
FL, USA
Before using a 10K pot let me readout the 47K one to see what resistance is needed for 2.7V. I'll get back to you this evening, if that is ok.
 
OP
Ace-a-Rue

Ace-a-Rue

Member
Joined
Oct 22, 2001
Location
FL, USA
Ok my friend, I read out the resistance and it was 11.7K ohms for 2.7V of Vdimm. Probably a 10K pot, if it reads out exact, should give you around 2.75 to 2.8V. The RS 10K (even the 47K) pots are not precise. Most times I would get a reading of 9.6-9.7 at max resistance. I had a very similar thing with my Rdram Intel board where the pot was reading at 9.7K. Rdram voltage is the same as DDR. So, I got about 2.82V on boot up with 9.7K of resistance. If you can live with 2.8+ right from boot then a 10K pot will give you precise control over increasing the Vdimm beyond 2.8V.

Give me feed back on how your Vdimm mod goes and what pot and voltage you got.
 
OP
Ace-a-Rue

Ace-a-Rue

Member
Joined
Oct 22, 2001
Location
FL, USA
An update. I switched over to a 10K pot which really read out at 9.6K. My 47K pot crapped out at the very low end resistance spectrum and therefore, it wouldn't give me anything above 2.74V.

The 10K (9.6) gave me about 2.75V at boot and a small turn to decrease the resistance put it at 2.8V. That allowed me to put back in my Samsung PC 2700 CTL stick of 512 MB. Running CAS 2, 5-2-2-2 at 150 FSB so I am a happy camper!:)
 
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