Asus v9280 - Ti4200 doesnt look like the others!

[texuspete00]

Hi guys. I bought this card from kunaak for a semi dated benching rig to learn some things. All the mods I find for the card.... well mine looks a little different. I just found out it is actually a Ti4200-8x. So maybe that is part of it but Icee's OTES article and others with 8x cards.... still dont look like mine :(

In this link I have three pics. One of the upper left on the back where the mem mod is usually done (Considering AGP connection the bottom). I also have where the gpu mod is usually done.... the upper - towards the right of the back. Sorry if thats confusing but the third pic shows the areas I took close ups of just to put it in perspective.

http://www25.brinkster.com/texuspete00/default.htm

I think the gpu mod shouldnt be too hard for someone who knows more than I to help because (as can be seen in the pic) it looks like there is a voltage regulater there labelled SC2602S. I dug up the datasheet for it here (but I couldnt find the S variant - just sc2602)

http://www.semtech.com/pdf/sc2602.pdf

I am a vmod noob but I guess the dimple indicated pin 1 and I want to get my VR on pin 11 (sense pin) as counted counterclockwise? This card may never play a game so if I can get the gpu mod done I'd be happy.... for now ;)

Sorry I couldnt just put the pics up in here. I have to get me some hosting service or something. Help!

[Edward2]

I could not find a datasheet for the S variant either, but I would guess that it is probably the same. Yes, the dimple indicates Pin 1 and you count the pins counter-clockwise. Pin 11 would be the center pin on the left (as shown in your GPU mod picture).

I would recommend you do the following:
1. With your computer running, measure the default GPU voltage on the + side of one of the capacitors on the video card. It should probably measure 1.5-1.8 volts. You can measure the voltage on the backside of the video card where the capacitor sticks through the card. You can then use this location to measure the GPU voltage after you install your VR.
2. Shutdown your computer and measure the resistance between Pin 11 and Ground. You can use the - side of the capacitor for ground if you want.
3. Now you can install a VR between Pin 11 and Ground. I usually install a VR set to 20x the resistance you measured in step 2 above.
4. Power up your computer. Now you can decrease the resistance of the VR and measure the GPU voltage. Depending on your GPU cooling, I would not raise the GPU voltage too much.

[texuspete00]

I check the resistance and I get, Oh soot I'll update with the exact, but it was like 6.8k! I couldnt get a solid reading until I adjusted the meter for up to 20k so Im pretty sure I did it right. I used the ground on the vreg. 20 times this you think.... where can I find such a VR?

[Hell-Fire]

You can run 2x10K VRs in a series to obtain 30 turns and 20K ohms.

Or you could buy a 50K VR off the web.

I had a Ti4200 once that required a 100K VR and a 200K VR for the mods.

[Edward2]

If you measured about 6.8k, then I would install like a 100k VR. That would give you about 15x the default resistance. You should be able to buy one either online or at a local electronics store. Set the VR to 100k and then lower the resistance as needed.

[texuspete00]

Whoops guys.... looks like my memory had failed me. The resistance of the sense pin to ground (used vreg ground pin) was 7.57k. So would this warrant opting for the 200k VR as 100k is quite a bit less than 20 times 7.8k. Or do they even sell 150k ones?

Being the impatient guy I am, I decided to put away the practice modem and make my NF7S my first vmod victim because I already had a couple 5k VR's. It was a success! It was bit more cramped than this will be as well. Feeling confident!:thumbsup:

[Hell-Fire]

Good luck.

Yes, I would go with the 200k if you abse resistance is 7.8k ohms. I would also consider running 2x100K VRs in a series to give you more control over adjustments versus buying a single 200K VR.

[texuspete00]

In series huh? How do I go about that? Oh and because the base resitance is so high, it will take a fair amount of lowering the resistance to make a difference no? You know how VR's seem to have a sweet spot where all of a sudden the voltage changes much more than it had been... is this going to be grossly over-exaggerated?

[Edward2]

You should be fine using a multi-turn VR for adjusting the voltage. The typical multi-turn VR takes about 12-20 complete revolutions to go from 0 to max resistance.

Yes it will probably take quite a few turns in order to increase the voltage, but don't go too fast. Take your time. Turn the VR some, and then measure the voltage. Keep doing this until you get the voltage you want.

[texuspete00]

Cool, Thanks. BTW, Smoking score on that Ti4200 of yours. :slobber:

Alright that takes care of my q's until/unless I decide to take it up a notch and figure out the mem mod. My second vmod will probably be as satisfying as the first considering it isn't really documented. I learned a few things etc. Cheers!

:toast: