Vmem VOLTAGE MOD GUIDE

Updated 05/11/02 by Tim B @ OCWorkbench.com

The orignial guide by hamahe
http://forum.ocworkbench.com/ocwbcgi/ultimatebb.cgi?ubb=get_topic&f=4&t=000802

Related threads.
...pics needed?

By hamahe
Ok if you are not very experienced in
soldering stop here with reading.
When you read on its at

Y O U R O W N R I S K.
Please dont blame me when your mobo is damaged!!!

The Voltage regulation is done by IC U15
which is a LM358 Double OP-Amp.
(Near PCI-Slot 2)

Pin 7 of it (Output) is connected to the
Gate of the FET Q30 (a L3103S 64Ampere Powerfet). (Near the SDRAM SocketNr2, 10cm
away from U15).
(U13 regulates the Termination Voltage of
the DRAMs to 1.2 V)

You can measure the Supply-Voltage for the DRAMs on the Source
of Q30 that is connected directly to the
DRAM-Sockets.

Now here how to change the Voltage:

Resistor 358 connects Pin 6 of U15 to ground.

Solder a Resistor of 1500 Ohms parallel to
Resistor 358. (From Pin6 U15 to ground).

And now your RAM gets 2.6Volts.

If you use a 750 Ohm you get 2.7Volts.

I've done it on my board together with L7
Bridge von CPU it runs at 150MHz.
(1600TBd now at 1600Mhz)

Good Luck.

(when SDRAMs are plugged in Q30 switches to
3.3 Volts. The modification has no effect
in this case.)

The Bios Hardware Monitor will NOT show
the increase of the Voltage, i really dont
know where they measure it (if at all???)

But the Voltage increases at the RAM-Sockets.