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Abit KT7A voltage mod

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Commited

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Joined
Feb 24, 2001
i've heard this mentioned a few times..
What does this modification do and how do i do it?
 

Shep

Senior Member
Joined
Dec 18, 2000
Location
Marshall, MO
The voltage mod lets you set the voltage higher than the bios will. basically you solder a couple variable resistors between pin 7 and ground and pin 10 and ground on the voltage regulator. I don't have the links to it on this pc or I would post them for you.
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
Solder wires to Pin 7 and Pin 10 of the IC that controls the voltage to the CPU. Put a 47K trimmer (49 cents at Radio Shack part # 271-283) between each wire and ground. Use a spade lug or loop under a motherboard mounting screw for your ground connection. For convenience I suggest you mount the trimmers on a piece of breadboard and secure it to your motherboard tray with Velcro.

Pin 7 controls the voltage, Pin 10 controls maximum voltage threshold. Turn the trimmers to full resistance boot your PC and start VIA Hardware Monitor. Set the polling interval to 2 seconds and slowly dial up the pin 7 trimmer until the voltage peaks. This should be about 2.1 volts. Then dial up the Pin 10 trimmer until your screen blanks and back it off a tad. Your PC will probably reboot when the screen blanks. Go back into VIA Hardware Monitor and dial the Pin 7 trimmer up to 2.3 volts. You may be able to go higher but I don’t recommend it.

Caution this will stress your cooling. Be careful or your CPU could end up a crispy critter. I also suggest buying a third hand device from Radio Shack to hold a pre-tinned wire to the IC leg while you solder. The magnifying glass on the third had will come in handy too. Get in and out fast so you don’t toast the IC. Lay off the caffeine and if you are of age, have a beer a half hour before soldering to steady your hands.

I’ll monitor this thread incase you have further questions.

[img="[URL]http://albums.photopoint.com/j/View?u=1551335&a=11768501&p=42534658[/URL]"]
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
Here is one more pic of how it looks on one of my boards.

[img="[URL]http://albums.photopoint.com/j/View?u=1551335&a=11768501&p=42534662[/URL]"]
 
OP
C

Commited

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Joined
Feb 24, 2001
Well, wow....
What could i get out of my duron 800 with this mod.
I'm scared to try it, because im good at breakin things!
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
Find a good radio shop and have them do the soldering to the IC for you.
 
OP
C

Commited

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Feb 24, 2001
Whats an IC? :D
What would I get out of a duron 800. Would it get me an extra 100Mhz over what i can get without it?
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
I can’t answer the Duron question, never owned one. With proper cooling I have been able to get an extra 100 mHz out of Birds. Others have done better.

An IC is an integrated circuit. It’s the thing the wires are soldered to in the pic I posted.

ONE NOTE OF EXTREME CAUTION: Be sure to keep the wires low on the board and anchor them with a zip tie. Not having done this yet, I snagged the wires hard enough to pull the IC pin 10 trace right of the board. Result? One terminally dead KT7A-R. Bare in mind I have done a number of boards and coached a whole bunch of folks through the mod. I never expected this! Off to Price Watch to find another board.
 

Bartman

Registered
Joined
Feb 9, 2001
Location
Yarmouth
When you raise the Voltage beyond 1.85v what parts on the MB are you stressing?

Forget about the CPU for a minute here of course.

I know a higher FSB will heat the Northbridge (I think I am correct here),
and I have heard that the MOSFET chips run hot... what exactly causes these to heat up so badly?

Also, what is the "I/O Voltage" mean, and what does it do? I have no experiance with this at all.. I hear of guys running it at 3.5v or 3.6v but I have no clue what it is / does.

-Bartman
 

Colin

Arctic Silver Senior
Joined
Dec 19, 2000
Since I did not design this series of boards, my comments on stress should be taken as observations. The voltage regulators are designed to take the heat. I don’t think raising the core voltage to 2.3 volts is going to kill them. It’s a rare Bird that needs anything over 2.2 volts and many of the newer Birds are unstable at 2.2 volts and above.

There have also been some folks that have commented on the voltage mod affecting the 3.3 volt and 12 volt output. I have not personally observed this and it may be related to the quality of the PSU. I have only run modded boards with a 400 watt Jinco (better build quality than Enermax) and a 530 watt Enermax.

The I/O voltage is the input/output voltage from your CPU. Up until the first Pentium processors for laptops were designed, all CPUs ran the same voltage in both the core and I/O. If you are raising the FSB, increasing the I/O voltage may help with stability. In rare cases you may need a higher voltage even if you are not increasing the FSB. The Matrox 450 video card I use requires 3.5 volts to be stable at a stock FSB speed on the KT7-Rs I have.
 
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Feb 24, 2001
I think i'll leave it for now...to much risk and its alot of money to replace.