Help please on a Vdimm mod on Shuttle sn25p

[turbo]

Hi can an experienced modder help me with a VDIMM mod on a shuttle SN25P. Ive read a bunch of forums and purchased a soldering iron and multimeter. Would love to give some BH5 a bit more voltage. Have taken voltages on the legs of 8 chips surrounding the DIMMs. Ive noticed a RT9173b chip which measures voltage I think. Its volts are 3.27,0.00,3.27,1.31,1.32 on the legs.

I kinda think the simplest mod is best for me so if some experienced modders could help me out it'd be brilliant.

Heres a pic of the area around the DIMMs. Can provide more detailed pics if necassary.

[persivore]

The RT9173b looks like the Vtt regulator. Can you tell me what is written on the two chips I have circled please.

[turbo]

Will take a look when I get back from work. The labeling was very faint. There are two more identical looking chips under the right side DIMM clips if that makes any difference. Cant see in this pic though.

[turbo]

Persivore thanks for taking a look.
I found out about the rt9173b on the richtech site. it says:
THE RT9173B REGULATOR IS DESIGNED TO CONVERT VOLTAGE SUPPLIES RANGING FROM 1.7V TO 6V INTO A DESIRED OUTPUT
VOLTAGE OF WHICH ADJUSTED BY TWO EXTERNAL VOLTAGE DIVIDER RESISTORS.
PIN 1 VIN
PIN2 GND
PIN3 VCNTL
PIN4 REFEN
PIN5 V OUT

Ive also written down the chip numbers and the voltages on 8 chips in the picture just to keep it all together. The chip leg voltages go top to bottom and left to right in the picture. The chip you circled on the left is the rt9202.

[persivore]

The RT9202 is probably the Vdimm regulator. Can you check the resistance between pin 6 and ground please.

[turbo]

The resistance on the RT9202 pin6 to ground was 0.064 Kohms. I didnt have the pc plugged in when taking the measurment.

[persivore]

For the Vdimm mod, connect a 5k (or 10k) VR between pin 6 and ground. Decrease resistance for more voltage.

note: XS owners and members will not be liable for any damage caused to you or your hardware, neither can be liable for any breach of the warranty.

[turbo]

Will give it a try. Copy that on the liability. If you dont try youll never know.

Thanks for the time persivore.

[turbo]

Persivore hello again.

Did a test run using IC clips instead of solder. Got the clip positioned so to not touch other pins. Have the lead from pin 6 going to the left contact of the 5K VR and the earth going to the center contact. When resistor is turned down there is no change in voltage shown in bios. Voltage is set to default. When turned more than half way the system shuts down. When resistance is lowered there is no improvement in overclock.

What should I try?

[persivore]

Sorry, I think that it might be my fault. I just looked over the voltage readings you took, and it looks like the voltage regulator which has been modded controls another voltage, and not Vdimm (possibly Vdd). It was probably shutting down due to OVP :eek:

What is written on the chip(s) under the Dimm clips to the right of the picture?

[turbo]

Hi there Persivore

I noticed that when I touched pin 6 on the initial voltage test the system shut down. I didnt mention it. Also I think the voltage readings shown in the picture are mirror reversed for pins 5-8.

F chip under the clip in the picture is ATMEL504, G is 358 E448 and
H is 44ABLM 431ACM. Its in the picture anyway.

Checked the resistance on the pins. G chip pin 5 is .875Kohm and on H chip pin 6 its 1.1Kohm and pin 7 its .717Kohm.

[persivore]

Can you check the voltages on the chip marked 358 (probably an LM358) at pins 1, 7 and 8. I know that you've already checked them, but they don't look right to me.
Can you also check the resistance between pin 2 and ground on the LM358.

[turbo]

Pin 1 (top right of chip) .079volts, Pin7 1.217 Volts, pin 8 0.0volts. I couldnt get a reading on the resistance pin 2 to ground. It just reads 1 on the multimeter. It may be 1Kohm but it always reads 1 by default.

[persivore]

Try connecting a 20k VR between pin 6 and ground on the LM358. Check that the voltage on pin 7 changes when you adjust the VR, and also check the Vdimm in BIOS or with a multimeter as you adjust it. If the voltage doesn't change after a few turns of the VR, remove the mod and post back :)

[turbo]

Shall do.

[turbo]

No change on the MM or the bios. It was reading 1.22Volts on the MM at pin 7.

[persivore]

What was the Vdimm set to when you took the readings? Can you find a point (on a MOSFET or capacitor leg) which reads Vdimm?

[turbo]

Found a new voltage reg chip. I should have noticed it before by the vdimm light label nearby. Its an RT9202. pin 4 shows the same voltage as the BIOS. 2.61volts.

Anyway a pic is attached.

[persivore]

That looks like the Vdimm regulator (hopefully it is actually the Vdimm regulator this time, and not for some other voltage ;)). Can you check the resistance between pin 6 and ground please.

[turbo]

The resistance shows no change from default.

[persivore]

What resistance range was your DMM set to? Can you use a higher range?

[turbo]

It was set to 2k ohm (the minimum) but I tried it on the other settings 20 and 200 kohm. It doesnt go any lower its an entry level unit only. Rechecked and still same readings. Ill attach the pic of the chip with the pin Im testing to make sure its number 6.

[persivore]

I can't see which pin is pin 1 from the picture, but I think its the one I marked. If its not, just rotate the picture (pin 1 should be marked with a dot near the pin)

[turbo]

Yes thats the way I tested

[persivore]

Can you check the voltage at pin 6? That should be enough to tell me if its the right pin :)

[turbo]

Its 5.47 volts

[persivore]

I think that might be the wrong pin then. I was expecting it to be about 0.8v. Can you check the voltage at the pin I've marked, and the resistance between the pin and ground.

[turbo]

The chip is 180 degree about. so the pin 6 is next to the one you marked and pin 1 is closest and right side. The voltage on pin pin 6 as shown is .80 volts

[persivore]

Thats what I was expecting pin 6 to read :). Can you check the resistance beween pin 6 and ground.

[turbo]

With the system turned off the resistance is .060k ohm and with the system turned on it shows no reading.

[persivore]

Try connecting a 5k VR between pin 6 and ground. Decrease the resistance for more voltage. Hopefully this will be the right mod this time :)

Note: XS owners and members will not be liable for any damage caused to you or your hardware, neither can be liable for any breach of the warranty.

[turbo]

Just lowered the resistance on the 5K resistor and pin 8 showed an increase in voltage. Up to near 2.9volts and then the system cut off. Im just using the IC clip still. The ram modules arent in yet, maybe thats it. Unfortunately I have to race off to work. Ill do some more testing tommorrow.
It was the right mod Persivore, well done and thanks for the persivorance. Ill do some more checking tommorrow.

[turbo]

Hey there persivore. Well definitely the right mod. Seems to be tons of volts I saw it go up to 3.8volts in the bios and could have gone higher. With the 5K ohm resistor its quite sensitive. 5 degree turn makes a difference of about a volt when you get to the right spot. Ive got it running at 3.3volts in the bios and thats 3.2 on the multimeter. It does 220 at 2,2,2,6 which is pretty good for me at the moment. When Ive tried more volts the system wont boot. May need more bios tweaking.

Got to say it thanks again. Couldnt have done it without your experience and know-how. Youve turned a complete novice into a modder. :toast:

Ill update if I can squeeze more out of the shuttle.

[turbo]

With a bit of tweaking its now at 244. 2,2,2,6

[TonyMontana]

old thread I know...just wanted to verify that the mod works fine (i did it with a 10k potentiometer) and now Im at 240MHz 2-2-6-2-1T Mushkin Redline XP4000 3.3V. I think this is the only thread on the whole WWW that provides this info (Vdimm mod) for Shuttle SN25P.

all kudos to persivore. he's the man. and thanks to turbo for asking!

[Nosfer@tu]

old thread I know...just wanted to verify that the mod works fine (i did it with a 10k potentiometer) and now Im at 240MHz 2-2-6-2-1T Mushkin Redline XP4000 3.3V. I think this is the only thread on the whole WWW that provides this info (Vdimm mod) for Shuttle SN25P.

all kudos to persivore. he's the man. and thanks to turbo for asking!

Nice of you to verify TonyMontana ;)

I think persivore appriciates that :)

[TonyMontana]

Nice of you to verify TonyMontana ;)

I think persivore appriciates that :)


thanks man.. i was looking for verification too but couldnt find any so I tested the mod to find out that it works properly - I was a bit scared to be honest. Since it succeded I thought I should let others know...

right now Im at 250MHz for Ram 2-2-3-6-1T and CPU at 2500MHz(10x, 1.475V), Chipset@1.7V. Also using an XFX 7900GT xtreme... extremePC@50C for the fan. Its all good ;) nice and stable.

[TonyMontana]

This is a pic of the Vdimm mod using a switch as well to cut off the mod if necessary. Do you guys know what the two potensiometers inside the Shuttle PSU do?