Need Vdimm and Vnbridge mod!!! Gigabyte 7S748 (SiS 748) mobo

[TiN_]

Plz help......

[TiN_]

Nobody knows?

[Hell-Fire]

Please post a pic of the board bud.

Pics of the dimm area, and areas above and below it are critical.

[TiN_]

Say what part you need.

It seems to me that there is two chips that are used for controlling voltages

One - near AGP Slot - its name is:

ICS CA331581

and another near DIMM slots

ICS UM94009

I didn't find any PDFs for this chips

[Hell-Fire]

Those are not the chips you need to focus on.

Look for chips marked LM348, or WinBond chips marked something similiar to W83303D, etc etc.

A pic would do a world of good man. If you cant take a pic, find one on the net and post it.

[Hell-Fire]

Get me the answers to what I cirlced please.

[TiN_]

I founded voltage regulator!

It is Richtek RT9173 in SOP-8 near ATX connector and PWR_FAN connector place.

But there is no PDF for this chip.

Also I found ECS Mobo with the same chip

http://www.xianbear.com/2/lib/200311/27/20031127180.htm

But it is not in english.
There is some pics there.

What I must connect together or what resistor I must use?

I want to get 2.9V on RAM.

[TiN_]

I measured voltages on this chip

Btw GND and pin 1 - 2.700 V - seems to be Vdimm/Vout
GND and pin 2 - near 0 V - GND?
GND and pin 3 - 1.36V --- ????
GND and pin 4 - 1.36V ---????
GND and pin 5,6,7,8 - 3.3V - Vin

[Hell-Fire]

Could be that this chip controls both Vdimm and Vtt.

Check the resistance between Pin #1 and #2 and post that please.

[TiN_]

BTW #1 and #2 - 100 ohm
BTW #1 and #3 - 100 ohm
BTW #1 and others - not measured

[TiN_]

I got PDF for this chip

R1 and R2 in it are 100 Kohm....mine are 100....hmm...

I upload PDF here: http://www.mgp.by.ru/1/PDF.zip

[Hell-Fire]

The circuit they have on the pdf is just a test circuit...not to mention that the resistors in the data sheet are most likely not connected to any of the other onboard resistance elements that are on the motherboard.

Are you saying that the individual resistances of your R1 and R2 are 100 ohms as printed on the resistor, or are you referring to the actual resistance read at each pin??

Regardless, it doesnt matter..but just so you know, the resistance read at those pins includes every other capacitor, resistor, or diode in that circuit.

If resistance is 100 ohms between #1 and #2, then try a 1K VR between those 2 pins to see if you can increase the voltage on pin #1 which I am assuming is Vdimm out.

A 1K VR will lower the resistance on pin #1 from 100 ohms to 90.1 ohms.

Let us know how things go.

If you have questions about how to add the VR to the circuit, pleas posts those before doing the mod.

[TiN_]

OK, I'll connect VR to pins 1 and 2..and post results if everything will be good.

There are also 100 ohm print on 2 resitors connected directly to 3rd pin

[TiN_]

I connected VR to 1 and 2
When I get resistanse lower that 500 ohm my Vdimm begin getting down
at 200 ohm I gen 2.40 V (without mod - 2.5 V)

What I must do to get HIGHER voltages?