need VDDRtt mod for KV8-MAX3

**overcrash86** · 07-07-2004, 02:55 PM

I search one vddrtt mod for my kv8-MAX 3 ,beacause ,it's stop at 2.8v (2.88 real)of VDIMM for stabilitiy beacause the vtt wasn't stable:

Code:

-------------------------------
BIOS     VDIM         VTT

2.5v     2.58v  ->  1.29v
2.55v    2.63v  ->  1.30-1.33v
2.6v     2.68v  ->  1.34v
2.65v    2.73v  ->  1.37v
2.7v     2.78v  ->  1.39v
2.8v     2.88v  ->  1.45v <- that good
2.9v     2.97v  ->  1.30v <- that bad
2.95v    3.02v  ->  1.33v <- that restart vtt
3v       3.08v  ->  1.35v
3.05v    3.13v  ->  1.37v
3.1v     3.19v  ->  1.38-1.41v
3.2v     3.27v  ->  1.45v
------------------------------

**Hell-Fire** · 07-07-2004, 11:12 PM

Can you point out where you are checking the Vtt? If the bios gives you a reading, please find the location on the board that is also showing you the reading.

I looked over all those pics and pretty sure where all the voltages are...but check again anyway. Make sure to mark where the Vdimm is increasing/decreasing everytime you make a change in the bios....do the same for the Vtt.

Thw W83303D shoulld be controlling both the Vdimm and Vtt. But I see 2 other Vregs near the dimms as well (LM431 and LM324).

Look over this pic. Give a resistance reading between the end of the resistor I circled. First make sure it is actually connected to pin #21 on the W83303D IC. It looks to be by following the trace, but better safe than sorry. Post the resistance you found and we can go from there and knock the Vdimm mod out.

Next, we have to find something that is connected to pin #7, or we will then have to cut a trace if no suitable resistor is located that is connected to it.

Do you know how to do connectivity tests between components?

**overcrash86** · 07-08-2004, 01:58 AM

all measures was took with VDIMM at 2.8v in bios (2.88v real), excepted this one :

http://forum.abit-usa.com/attachment...&postid=361593

the vdimm was at 2.6v in bios (2.68 real)

i vew the vtt in the uguru utility :

(the BIOS voltage selected was 2.8v)

**overcrash86** · 07-08-2004, 02:55 AM

this repnd with your questions ?
and now ,the mod it possible or not ?
if yes ,with what modifications ?

**Hell-Fire** · 07-08-2004, 09:37 AM

Ok, here we go:

For the one above on pin #21, remove the resistor that is 684ohms and replace with a 1K multi-turn VR set to 648ohms and adjust to increase the Vdimm.

Let me think a little more on the Vtt mod for pin #7. You show that this pin is connected to the spot on the board (which is a missing positive side of a capacitor), and "other resistance". Where is this connection being made?? If we are lucky, we can find a resistor to work with versus having to cut traces.

**bh2k** · 07-08-2004, 10:18 AM

Don't you wish everyone was this prepared when they asked for volt mods?

**overcrash86** · 07-08-2004, 10:18 AM

i haven't a trimmer ,at this time ,but i recive one this week-end probably ,this is the second pin connected to pin 7 :

**Hell-Fire** · 07-08-2004, 04:09 PM

Originally posted by bh2k
Don't you wish everyone was this prepared when they asked for volt mods?

Thank you sir.

I would think that if we cut the trace between those 2 SMD capacitors, and apply a VR between them....we could increase the Vtt without an issue at all.

We are simply wanting to add a resistor to the circuit so that our Vreg (W83303D) thinks it needs a little more voltage supplied.

Make sure that those SMD capacitors that are connected are reading the same voltage as the solder pad thats before them.

Also, there has got to be somewhere else to check the Vtt other than the solder pad. Something in the same circuit, but past the small SMD caps.

Man, if only I had some of these boards in front of me to look over.

**overcrash86** · 07-11-2004, 07:17 AM

I have try this :

removed 684ohm resistor ,end replaced with trimmer set to same resistance of 684ohm on motherboard ,and it doesn't work ,the VTT doesn't change with vdimm ,it change only vdimm.

**Hell-Fire** · 07-11-2004, 10:44 AM

Yes...the Vtt will not track the Vdimm after mod.

So, are you saying that changing resistor I recommended do in fact allow you to increase the Vdimm with the VR?? If so, then we can atleast say we have the Vdimm mod figured.

I will look over the Vtt again later on today.

**overcrash86** · 07-11-2004, 10:51 AM

The vdimm change only when i set 2.9v into the BIOS ,between 2.5v and 2.8v the vdimm doesn't change with VR ,that only after 2.8v ,between 2.9v and 3.2v ,and the max set value was 3.26v

**Hell-Fire** · 07-11-2004, 12:12 PM

The max Vdimm is prob due to a low 3.3v rail on the psu. This board must be fed Vdimm via the 3.3 v rail.

Not totally surprised about the fact that the VR doesnt work except between a certain range of Vdimm settings....what is odd tho is that its totally opposite from that of the IC7 board that uses the same W83303D Vreg.

On the IC7, you have to keep the Vdimm below 2.8v or the Vdimm automatically drops to 2.7v if a higher value is selected in the bios.....this is the case after the mod is performed.

Your pic links are dead bud....can you post another one showing more of the area including the W83303D chip and the dimms?

**Hell-Fire** · 07-11-2004, 12:17 PM

Take a resistance between these 2 spots that I mentioned above and hopefully we can finish this up.

**overcrash86** · 07-11-2004, 12:25 PM

**Hell-Fire** · 07-11-2004, 12:31 PM

Another question. What are the markings on these 2 ICs?

**overcrash86** · 07-11-2004, 12:36 PM

http://perso.wanadoo.fr/overcrash86/...f/100_2671.jpg

http://perso.wanadoo.fr/overcrash86/...f/100_2672.jpg

**Goldlocke** · 07-16-2004, 12:20 PM

Hey guys! Whazz up?

Have you 2 succeeded in the Vtt mod for the KV8-MAX3?

Cause I got a new challenge for Hell-Fire -> KV8Pro rev 1.1 uses same Winbond IC, but slightly different layout around it.
The problem stays the same: Vtt will only track up to 2.8V Vdimm.

Hell-Fire u got PM!

**overcrash86** · 07-16-2004, 12:43 PM

Originally posted by Goldlocke
Hey guys! Whazz up?

Have you 2 succeeded in the Vtt mod for the KV8-MAX3?

Cause I got a new challenge for Hell-Fire -> KV8Pro rev 1.1 uses same Winbond IC, but slightly different layout around it.
The problem stays the same: Vtt will only track up to 2.8V Vdimm.

Hell-Fire u got PM!

we haven't find the good solution ,but i've try one of the possibility ,and it doesn't work well. I search more mod ,only for the vtt ,because the vdimm was changable in the BIOS ,i think if i set manually the vtt on the bank of memory , same as the vdimm mod rail +3.3 ,with one regulator between the +5V or +3.3 (probably 3.3v) and the pin to have the vtt on the dimm bank,
but i don't know where is the VTT ont the bank of memory

**Hell-Fire** · 07-17-2004, 07:50 AM

Originally posted by Goldlocke
Hey guys! Whazz up?

Have you 2 succeeded in the Vtt mod for the KV8-MAX3?

Cause I got a new challenge for Hell-Fire -> KV8Pro rev 1.1 uses same Winbond IC, but slightly different layout around it.
The problem stays the same: Vtt will only track up to 2.8V Vdimm.

Hell-Fire u got PM!

I need a pic of the area around the IC so I can have you check a few things.

**Hell-Fire** · 07-17-2004, 07:53 AM

Originally posted by overcrash86
we haven't find the good solution ,but i've try one of the possibility ,and it doesn't work well. I search more mod ,only for the vtt ,because the vdimm was changable in the BIOS ,i think if i set manually the vtt on the bank of memory , same as the vdimm mod rail +3.3 ,with one regulator between the +5V or +3.3 (probably 3.3v) and the pin to have the vtt on the dimm bank,
but i don't know where is the VTT ont the bank of memory

Cant you post a pic of a larger area to the right of this pic?

Include everything thats in this pic, just a larger area covered.

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