ABIT KV8Pro: Vtt mod

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Originally posted by Hell-Fire
I fail to see why a fixed resistor is needed for this mod.

Although Hipro also used fixed resistors in his guide to the IC7 boards (for Vtt & Vagp mods), they were not needed there as well.

I straight thru VR should have done the trick as well.

The way I am looking at that above, it would prob still work just to remove the whole setup in the above pic and solder the VR between pad #1 and the FET leg reading Vtt.

Hipro, could you clarify this for me as it may help me with future mods. Resistance is resistance, and when a zero ohm resistor is removed, its no different than cutting a trace and introducing a resistance into the circuit loop to increase voltage.

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If the VTT sence of the winbond IC needs a few uA to work and not mA , then even with a 1K Ohm resistor we get nothing(or a few-readable)......If our "sence" pin needs mA to work , then involving a resistor will do the job BUT not well above some Volts........The R-R(ground) method,forces the cirquit to lower the reading voltage as we wish(trimmed) and it feeds the "sence" cirquit with this voltage and with the uA or mA it wants.... ;)
No matter what it will work....... ;)

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Originally posted by hipro5
If the VTT sence of the winbond IC needs a few uA to work and not mA , then even with a 1K Ohm resistor we get nothing(or a few-readable)......If our "sence" pin needs mA to work , then involving a resistor will do the job BUT not well above some Volts........The R-R(ground) method,forces the cirquit to lower the reading voltage as we wish(trimmed) and it feeds the "sence" cirquit with this voltage and with the uA or mA it wants.... ;)
No matter what it will work....... ;)

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I figured it was something along those lines, but wanted to get your input.

This is along the same lines as a controller passing binary 1 and 0 calls to regulate voltage.

So, the fixed resistor forces the current high enough for the sense pin to output stock Vtt as regulated by W83303D, then we control further output via the trimmer.

Reason I was asking mainly is because I had similiar issue with the AK89 board where the W83304D was present and zero ohm resistors were both in the circuit of Vdimm and Vtt regulation. I replaced both with 200 ohm VRs and could easily adjust both voltages.

Goldlocke - just wandering what are you running you rails at, 12v,5v, & 3.3v .

How is the mod working, I have this board & would love to get some BH6 kickin in it.

Can anyone put here a picture with the final mod and the values of the resistors?


Thank you

that is my KV8-MAX3 ,but i didn't find the good vtt mod ,i have try one mod ,but it doesn't work ,but your motherboard it more same as my because your resistore was placed same as the KV8-MAX3 ,and i have the same measure. I will try your vmod on my KV8 , one picture for explain :

http://perso.wanadoo.fr/overcrash86/...esures/vtt.gif

What do you guys think of this??

http://www.savepic.com/freepictureho..._mosfets2E.jpg

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Originally posted by CaTalyst.X
What do you guys think of this??

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I think it would work....... :)

Good :P some1 wanna test it?

-CaT

@ Overcrash, give this a try.


http://www.savepic.com/freepictureho...6&img=vtte.jpg

-CaT

well i had this board lying around and decided to see if connecting the 3.3v rail directly to the vdimm would work. it seems it worked perfectly. i dont have a cpu to test it though. only checked it with the multi and the fet was reading 3.3v instead of the default voltage after the mod. here is a pic of the mod.

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Originally posted by CaTalyst.X
@ Overcrash, give this a try.


http://www.savepic.com/freepictureho...6&img=vtte.jpg

-CaT

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Thanks CaTalyst.X,

I will test when I would have a trimmer.

at this moment i have oen Chaintech VNF3-250 and it work better as the KV8-MAX3 ,for OCing :D 360Mhz of FSB stable ,i'll recicve my ADATA PC4000 tomorrow ,i've alredy do the vdimm mod on the vnf3 and it was at 3.37v :D .

Alrighy, let us know how it goes :D

-CaT

how would the vdimm mod go? i know theres the 3.3v from the ps, but how could u do it with a vr? i want to be able to get up to about 3.4v, but down to 3.0
has anyone had problems lately with this board and the memory controller at high voltages?

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Originally posted by hipro5
NO.....You have to start at high resistance on my mods(IC7-G) based VTT......IF you solder ONLY a trimmer in R19's place , then YES trim it at low resistance......

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Let me get this stright, for 10ohm Fixed Resistor + 200ohm VR set-up I'll need to set the VR at 200ohm. Then reduce the resistance to get higher VTT?

tried it. does not work! :(

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Originally posted by CaTalyst.X
What do you guys think of this??

http://www.savepic.com/freepictureho..._mosfets2E.jpg

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Now I have a Serious Problem. One of the Soldering points of the R19 came off! :eek: It's the one nearest to the Mosfet. Help would be Really Really Good. :(

Are you saying that the solder pad on the motherboard came off, or just the solder on the end of the resistor?

Using the pic above, please point out which spot.

http://img.photobucket.com/albums/v1..._mosfets-a.jpg
It's the PAD. Refer to Pic above. Yellow Arrow, Soldering Pad on the Right side.

And I tried digging the point with a pen knife. which was a big mistake.

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Originally posted by Hell-Fire
Are you saying that the solder pad on the motherboard came off, or just the solder on the end of the resistor?

Using the pic above, please point out which spot.

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You can fix that easily I think by soldering a wire across the 2 points I marked. Or, to make it easier, just connect the points using solder itself.

Should fine since that was a 0 ohm resistor and I dont see anything else that the right solder pad is connected to that should be connected in the circuit.

Hell-Fire Thank you. I'll try this.

Cheers man. :)

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Originally posted by Hell-Fire
You can fix that easily I think by soldering a wire across the 2 points I marked. Or, to make it easier, just connect the points using solder itself.

Should fine since that was a 0 ohm resistor and I dont see anything else that the right solder pad is connected to that should be connected in the circuit.

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I have reconnected the wires as per your pic.
http://img.photobucket.com/albums/v1...ods/KV8Pro.jpg
Question, How do I go about if I want to do VTT mod?

Right now I am at school, so I dont have time to read over the entire thread again to see what, if any, progress has been made.

If R19 was the proper resistor off the Vtt Vreg, then I recommend putting a 10-20 ohm fixed resistor between the 2 solder pads, being careful not to bridge together the solder pad on R20. Then, connect a wire to the end of that fixed resistor that is soldered to the pad to the left of R20 pad (using hte pic in your last post), and solder other end of that wire to a 200-1K ohm VR set to max resistance..and other leg of VR to ground.

Remember to use the middle leg and one of the outter legs.

That should do the trick is R19 is directly connected to pin #7 on WinBond.

you can still do the vtt mod, just use the alternate pad that HF pointed out instead of the one you burned out and do it like this:

http://www.xtremesystems.org/forums/...282#post498282

I would be really interested in this, to see the mod on rocking ;)
Anyone knows if Abit will come up with a bios that can let us adjust the vdimm up to 3.2 ???

The uGuru that came with the installation CD is able to adjust the VDimm to 3.2v. But the problem is that the VTT only follows up to 2.8v. anything above it will not follow.

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Originally posted by Byron
I would be really interested in this, to see the mod on rocking ;)
Anyone knows if Abit will come up with a bios that can let us adjust the vdimm up to 3.2 ???

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