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3BABY
02-10-2009, 07:06 PM
Hey Guys,

have noticed there is a few non-reference 9800GTX's around, it seems XFX has used a different PWM controller to what is used on the reference models, i cant seem to find any real or downloadable datasheets or information from other card vmods using this chip, below is a pic of the unit, and another chip i suspect my have the mem side of it, any help would be much appreciated.

We have a RT8841 below

http://img3.imageshack.us/img3/7543/img0013eq3.jpg (http://imageshack.us)



uP6161S14 EGF7AF, the syspected mem voltage controller below

http://img144.imageshack.us/img144/7817/img0014vc1.jpg (http://imageshack.us)



and a pic of the relative positions on the board

http://img3.imageshack.us/img3/7370/boardes4.jpg (http://imageshack.us)
ceemic
02-11-2009, 01:38 PM
I'm pretty sure FB on RT8841 is pin #4. Measure its default resistance between GND and use 20x times VR to be safe. Vgpu should change a little bit even on max resistance on VR. Or You can make some turns to lower the resistance few %. If Vgpu doesn't change at all, then unsolder the VR...
3BABY
02-13-2009, 10:58 AM
I'm pretty sure FB on RT8841 is pin #4. Measure its default resistance between GND and use 20x times VR to be safe. Vgpu should change a little bit even on max resistance on VR. Or You can make some turns to lower the resistance few %. If Vgpu doesn't change at all, then unsolder the VR...

thanks for the reply,

ive managed to get the datasheet, and from what it says FB is pin #6. so it should be the one with the green arrow in the second pic?

http://img9.imageshack.us/img9/647/picture0001ia1.jpg (http://imageshack.us) http://img528.imageshack.us/img528/4999/32676826wx0.jpg (http://imageshack.us)
ceemic
02-13-2009, 12:07 PM
3BABY, can You share this datasheet? FB is pin #6.
3BABY
02-13-2009, 01:45 PM
3BABY, can You share this datasheet? FB is pin #6.


ok, i screwed that up a lil, have edited my above post to reflect the new info.

datasheet can be found here (http://rapidshare.com/files/197753605/DS8841-02C-elecfans.pdf.html) (note wont be there forever 10times apparently )
Riska
03-14-2009, 11:45 AM
The mod works i have made it on a xfx 9800gtx+ and i used a 50k ohm vr for vmem and a 100k ohm vr for gpu
Tommie_lj
03-17-2009, 11:23 AM
im planning to buy a XFX GTS 250, wich from what ive heard is the same card as this one? so is it possible to vmod it exactly as this one or is there another mod for that card?
largon
03-20-2009, 07:45 AM
If hardware is the same then the mod works.
AfsFaes
02-13-2011, 01:40 AM
hi guys, i'm a new user and i have the same card.

Please someone can explain me what point i have to connect?

For the v-core i have to connect a 100k resistor to pin 6 to ground, i'm in right? But for the v-mem how can i do? someone tell me where is the measurment pointso of the voltage?

thanks for the reply