hmmm plz tell me which resistors and poti's to use... im stuck at 225 (corsair pc3500) / 223 (kingston hyperx) :(
Printable View
hmmm plz tell me which resistors and poti's to use... im stuck at 225 (corsair pc3500) / 223 (kingston hyperx) :(
EDITED, sorry released this was VDimm not VDDR (thanks muzz :D)Quote:
Originally posted by xtreme
hmmm plz tell me which resistors and poti's to use... im stuck at 225 (corsair pc3500) / 223 (kingston hyperx) :(
Wooooooooooo boy!!! We are talking vdimm here, not the vdd.
Here is what Jeff said, and he's done it.
"What resistance are you adding across the cut trace? You should be starting at ZERO Ohms and then working slowly up. Vdimm will top out ~300 Ohms at 3.2x volts and if you add too much resistance, strange things could be happening. I know my BIOS, MBM, and USDM all don't like when I have too much resistance."
Jeff,
Is it also possible to connect one end of a resistor to Q32 output pin (STR1) and the other end to GND? It's a simple voltage divider circuit. It will drop the volt across the circuit without doing any cutting on the board.
Don't know. You'll have to wait for someone more intelligent to come around for the answer to that question. ;) My gut says no, but I really dunno... :confused:
Hmm.. I thought about it again.
Unlikely since that is a true drop in Vddr at STR1. This will force volt regulator to increase Volt. End up running volt regulator at 3.2V but get real 2.8V output.
I know now. The trick is only to fool a volt regulator but not to do the actual volt drop.
I am trying to understand this mod.
If anyone have any idea, please help.
What Jeff has done is to use a resistor to connect the output pin of MOSFET (STR1) to Vsense pin of the volt regualtor (after cutting the trace).
To my understanding, a resistor works by limiting CURRENT flow. Putting a resistor between those pins limiting the current to Vsense. So I don't understand how this mod work.
To my understanding, a volt divider circuit between STR1 output and Vsense pin will actually drop the volt (together with cutting the trace that Jeff did).
STR1 (MOSFET output)
|
VR1
|----------Vsense
R2
|
GND
Then volt will be adjusted by VR1. Starting from 0 Ohm. Raise the Ohm until the desired volt is achieved.
Any idea?
All the resistor is doing is dropping some voltage. Pin21 monitoring Vdimm and if/when it gets a little low, the chip will compensate. What we are doing is faking it out. We are making it think that it's still trying to hold the voltage to 2.9v by stealing .2v or .3v. Pin21 is still getting 2.9v but everything else is getting 3.1 or 3.2v.
Everything except the Vdimm sensor. :D
call me a newb guys but do i use a 1/2W resistor or 1/4W?
A 1/4 W.Quote:
Originally posted by eliteone
call me a newb guys but do i use a 1/2W resistor or 1/4W?
But like Jeff already pointed out,it is much better to use a Variable Resistor since the "space" you can play with is very small.
From my experience with this mod i can say that 20-30 Ohms can make a huge difference on the resulting voltage!
bye
Crozet
does this apply to the VDD mod as well? Using a 1/4W i mean.
yes alwaysQuote:
Originally posted by eliteone
does this apply to the VDD mod as well? Using a 1/4W i mean.
bye
Crozet
NP BB.........;)
hi,
the v-ddr MOD work fine :D THX Jeff
timing: aggressive 7,2,2,2 3.1 v
http://membres.lycos.fr/ftpad/images/3702.png
Boy oh boy is that some bandwidth!!! :eek:
:toast:
I came across this Vddr mod guide.
They did Vbt as well to improve stability.
In the guide, they said that Epox is likely to include Vdd adjustment into BIOS as well.
Vddr mod guide
You can get Vddr to 3.48V??? Lets see a screeny with that!!! :eek: ;)
sorryQuote:
Originally posted by Jeff
You can get Vddr to 3.48V??? Lets see a screeny with that!!! :eek: ;)
the voltage is fixed at 3.2v :mad:
Ok, that's what I thought.
Any idea what the Vbt mod actually does? And do you really think it stabalizes anything? :confused:
Also, do you think the Vdimm measurement is measuring that Vbt and times that by 2? I've only done the Vddr mod and I can't get accurate software measurements.
'k... starting to think out loud again... :D
And I'm ignorant as to why you would ground the other lead of the VR? :confused: Anybody know why you'd do that? Does it actually change the measurement of the two pins you used? Or is it just a good practice to do so?
Text is wrong for the Vbt mod. That second blue wire(which goes to the top transistor) is NOT connected to ground. That's where Vbt is... definitely NOT a ground.
The only ground wires are the TWO brown wires. Each of the blue wires is acting as a sense line... one for the Vddr and one for the Vbt.
In that guide, he could have USDM measured Vddr volt.
Cut another trace again and connect BTsen with Q33 is the VBT mod right?!Quote:
Originally posted by Jeff
Text is wrong for the Vbt mod. That second blue wire(which goes to the top transistor) is NOT connected to ground. That's where Vbt is... definitely NOT a ground.
The only ground wires are the TWO brown wires. Each of the blue wires is acting as a sense line... one for the Vddr and one for the Vbt.
But is this neccesary?! Or is it just for reading the correct values in the BIOS :confused:
bye
Crozet
where to find the datasheet of this chip?