Help a noob set his v-meter for my first v-mad.

[krag]

I have read runmc's thread on the 9800 GPU V-mod and I know where & how to solder the V-R and measure the voltage of the GPU. I just don't know how to set the V-R to the GPU's default of 1.7v. I just built the V-R and have it hooked up to the meter. I have the meter set to 20k on the Ohms selection and when I turn the V-R screw clockwise the numbers decrease. When I turn it counterclockwise the numbers increase.
1) Do I have the meter set right (20k)
2) Which number value is the default of 1.7v? The number sclaes from 1 to 20+

Here is a pic of where I have it set at currently:

http://home.comcast.net/~krag81/DSCN0602.JPG

[CATCH22ATPLAY]

Well first off it sounds like it works right. When you turn it clockwise ohms should get lower and counterclockwise ohms should get higher. So turn it all the way counterclockwise for highest omhs. If it's a 20k ohm VR then set your meter to 20k ohm, like it is now. That will be your starting point and closest to default Vcore. As you turn the VR clockwise ohms will decrease and volts will increase. Be aware that if your gpu Vcore was at 1.70 before you did the mod it may be at 1.75 even with your vr set to 20k ohms. I actually use a 5k ohm vr myself. But i've also noticed quite a bit of a difference between my cards default ohm reading on pin 18. One of em is 224 ohms and the other is 400 ohms. I just wanted to warn you in case you buy another card to make sure you always start with that vr all the way counterclockwise. My 400 ohm card with my 5k ohm vr set at 5k ohm raises Vcore to 1.85 and it only goes up from there. Not a problem for me but be wary.

Oh and you set your meter to 20k for a 20k ohm resistor or less and 2000 for a 2k ohm resistor or less and set it at 200 for a 200 ohm resistor or less. If you use a 50k ohm resistor you gotta use your 200k ohm setting on your meter. If you use a 200k ohm resistor and you eventually decrease ohms to below 50k ohms then you can switch to 50k ohm selection and so on and so on. Weeeeeeee :)

[krag]

THanks for th ereply bro. Its actually a 10k v-r from radio shack. I wonder why it goes past 10k? Do I still use the 20k selection on the meter for a 10k v-r?

[CATCH22ATPLAY]

Yes you use the 20k selection. I don't see yours going past it. In that pick you got a reading of 8k ohms. Been quite a while since i've used a meter like that btw. But i'm fairly sure.

[krag]

One last noob question. When I decrease the ohms to increase the voltage...am I supposed to have the pc turned off when I turn the adjustment screw on the v-r?

[CATCH22ATPLAY]

If you have a 20 turn pot or higher you can do it live. Otherwise turn the pc off and unplug it. I suggest because you are new at this to unplug it and ohm it out. Ohm out pin 18 if that's the way you're modding it. See what ohms are without mod first and write down ohms and check volts live. Add you mod with 10k ohm already set and check again pin 18 and see what ohm reading is. Go live again and check volts. From just doing that you can then calculate what ohms on pin 18 will give you what volts. for instance if pin 18 was

400 ohms = 1.60v
375 ohms = 1.70v

then we know that 350 ohms will equal 1.80 without even checking volts. Best and safest way to do it. Keep you from giving it 2.20 volts by accident. Now back to me doing another new vid card volt mod.

[krag]

Thanks for your help bro!!!! now I just need to muster up enough guts to do the last part...solder & crank it!!!!:up:

[kingassasin]

Catch, or anybody. I tested a 10k pot before putting it on and got 10k. After I soldered it on, I retested ohms and it reads 222.35. Is this correct. I just don't want to fire it up and fry it. Please help anybody.

[CATCH22ATPLAY]

Dude not all R9800's are the same. Even a true ATI one may be different. Even without it having a revision number. As i've noticed in the past i've had several different reading between cards 224 ohms and 400 ohms to start before mods. So you need to ohm it out before modding it. More than likely if your 10k ohm pot is set and tested to be at 10k ohm then it should be fine. But since i don't want to get blamed for frying it please do as suggested just to be safe.