NF7-S Vdmm Vtt Mod Problems

[itshondo]

I decide to finally do the dirty punk Vdmm and Vtt mods to my NF7-S rev 2.0 (all black Mem slots)- I wanted to increase the Vdmm to my 2 X 512 Mushkin PC3500 Lvl 2 Black BH-5 memory to get my FSB past 225.

I modded the board as pictured below, without doing the Vdd mod. I made the jumper wires long enough so that I could cut them if it failed. It was a good thing I did because my rig would not even power up withe Vdmm jumper connected.

After cutting the jumper, it powers up fine. I cut the Vtt jumper first, but it still w/n power up with the Vdmm jumper connected.

My Fortron PSU is putting out a solid 3.3 volts, and I did not increase it at all.

I installed the jumper wires EXACTLY as depicted, good clean solder joints.

Any advice is appreciated.

 

[The_Jizzler]

as weird as it may sound, i have a pair of bh-5 that freaks out if the voltage is over 3.24v. and when i say that if its +.02v more than that all sorts of probs pop up. i got the same board, but my vdimm mod is the original one thats done on the other side of the board. no vtt, dont think i need it. all votages are spec on, as checked with dmm. ram hits 255 max memtest stable, with tight timings (2-3-2-11). i guess my point is i have discovered the voltage ceiling for my bh5, maybe your past yours at 3.3. try the mod the other way and see if you can bump it up gradually and see how you can go.

 

[itshondo]

I thought the BH-5 was good up to 3.6 volts?

The really strange thing is that it won't power up at all-

 

[Milkman]

I performed the Dirty punk Vdimm mod but did not do the Vtt and after adjusting my 3.5 I was easily able to send 3.4 to my BH-5 and cleared 245 no problem at all, I am not sure why you are having trouble, just recheck all and measure voltage at the Board plug under load for accurate measurements.

-Milkman

 

[The_Jizzler]

it can tolerate 3.6 and not self destruct. just like my cars 4cyl engine CAN turn over at 8000rpm and not self destruct. doesnt mean its optimal or even advisable. whenever pushing the limits to the max on equipment, all sorts of oddities/bugs will pop up.

all im getting at is i bet if you dropped the voltage to say around 3.1-3.2 you might have some success. obviously where your at aint gettin you squat, and the only thing different is youve jacked the voltage alot, at once.

 

[itshondo]

would dropping my 3.3 volt rail in my PSU affect anything else?

It is adjustable-

 

[felinusz]

Don't undervolt your +3.3VDC rail. +3.3VDC is also known as VI/O, because this rail powers pretty much all of the onboard I/O devices on your motherboard, incuding the VAGP, Northbridge/Southbridge VDD, and SATA controller. Drooping your +3.3VDC rail will likely cause some problems with your board. It won't kill anything, but it will almost certainly mess stuff up.


Which PCB revision does your NF7-S use? The revision number is in the top right hand corner of the board, when viewing the rear of the board's PCB. I'm of the opinion that the VDIMM=VI/O mod wasn't what caused your board to stop posting, but rather the VTT mod. Depending on your motherboard revision, certain VTT modification methods can kill boards, or cause them to cease functioning with the mod installed. Which VTT mod did you install?


With my old NF7-S, I increased my VDIMM with a traditional VDIMM voltage regulator potentiometer mod, combined with a +3.3VDC rail overvolt. Worked like a charm after a VTT mod . A VDIMM=VI/O mod, combined with an adjustable +3.3VDC rail would accomplish the same thing of course (raise your +3.3VDC rail to increase VDIMM past 3.3V). I should think that you would need to use the 'trace cut' VTT mod with such a setup however.

Check out this thread: http://www.ocforums.com/showthread.php?t=356979

 

[itshondo]

it's a rev 52 , same that you posted in a earlier thread I read-

I bought it late 2003- black dimm slots.

very frustrating....

 

[wannaoc]

I was trying to do this type of mod on a board recently and I had a similar problem. I was also using a Fortron with very stable lines but it did indeed turn out to be the psu. If you can swap it out and see if it works.

You might try turning up the 3.3v to at least .2 above what you want your ram at. I'm not sure about this mod version but with the normal resistor mod I had to keep my 3.3 that far above where it was set. I would bet its the psu though.