AN7 Vdimm mod gone Bad, need help!

[Darien]

Hi guys,

I perfromed the AN7 Vdimm guide posted here:
http://www.vr-zone.com/?i=759&s=1

and it works fantastic Thx!! actually I was advised to just solder a wire to the r316 resistor solder the other end of the wire to a VR - trimmer and then ground the 2nd leg of the Trimmer.

This is a picture of my motherboard with the modifications
http://www.ocforums.com/attachment....tid=43445&stc=1

and it worked great for over 1 week doing lots of testing and tweaking, no problems! but then my stupidity set in... I did a big NO NO and adjusted the voltage with the computer running and I fried the resistor because of a volt fluxuation... I think... the resistor is grounded now? and now the board still works, but the Vdimm is stuck to MAX... the same as the 3.3v rail... and I can't turn it down in the BIOS or with the Trimmer...

after trouble shooting I realized that the right side of the R316 reistor has 3.5 volts(the side closest to the RAM slots), while the left side has almost no voltatge at all.... AND the left side of the resistor has zero Ohms resistance to any ground point on the board...

Unfortuneately I think that maybe I didn't fry the resistor, but rather the circuit that leaves the left side of the resistor...

can anyone here give me any insight on how to fix this? I would unsolder the resistor and replace it, but I'm not sure thats the problem...

This isn't my first volt mod and any help you guys can give would be very much appreciated.

TIA

P.S. I think I know 1 way to fix/work around this, but I'm hoping to find out exactly what happened and maybe fix it the correct way.

[WannaOC]

Have you totally removed the vmod and tried to start it up?

[Darien]

Have you totally removed the vmod and tried to start it up?

Yes, totally removed, and it boots fine and runs fine, but again the Vdimm is stuck at the max, same value as the 3.3v rail... and the Vtt is still tracking correctly too.

[cirthix]

methinks that was dumb...

[cirthix]

o, here's your work around:
get winbond-based ram :P

[Darien]

methinks that was dumb...

o, here's your work around:
get winbond-based ram :P
Yeah, stuff like that's just not helpful, seriously if you don't have anything to add to the discussion, the least you could do is not spam...

btw, I do have G.Skill Winbond BH-5 UTT RAM, but it sucks, and I want to use my TCCD RAM... and I'm not interested in Ignoring the problem but fixing it.

xtremesystems is full of people with a wealth of technical knowlege, I'm a little disappointed, out of the 3 forums I've post on for help, this is the only one that no one has responded to me on...

I know there are people here who can help... any takers?

[Malves]

You know, I don't know why the hell some ppl think they are funny when they are trying to be funny, and they actualy are not. Got it?

Anyways, just remove the SMD resistor and do the mod the way it is supposed to be done.

[Darien]

You know, I don't know why the hell some ppl think they are funny when they are trying to be funny, and they actualy are not. Got it?

Anyways, just remove the SMD resistor and do the mod the way it is supposed to be done.

Wow...:eek: Hey Malves, I came across links to your mods but they were dead, glad to see your site it up, just checked it out, good stuff.... Nice to meet ya, Thx so much for your help, I know you know alot about this stuff...

lemme give you a little more detail...

the SMD resitor is firmly attached with no problems, clean too, no solder left on it from the mod... it may be blown though...

When I said earlier that I thought I knew the fix, this was what I was thinking of...

http://www.motherboardfaqs.com/abit/abit_mods_vdimm_files/1alt_method.jpg
just remove the resistor and like the pic shows, don't reattach the left side of the old resistor point, (which is a dead ground now) and instead just route it straight to the Vdimm Mosfet... then attach the VR to that... I'm pretty sure that will work... but I don't know 100%, and if that does work I don't know if my Vtt will still track and If I can still turn down the volt in my Bios.... but at least is will let me turn down the Vdimm....


Now, your basically saying replace the R316 resistor... well... I thought of that... but I'm not sure the r316 resistor is the problem...

The left solder pad of the r316 resistor is grounded. Is it normally a ground point? if it's normally a ground point then I'd definately replace it... but I was thinking the line to the left solder pad was ruined, cuz it is now grounded and therefore needs to be bypassed with the mod I posted above.... see the left solder pad of the r316 resistor has 0 ohms resistance with any other ground point on the board, which is like my grounded VR being set to 0 Ohm, which results in FULL power to the Vdimm... which is where I'm at currently

Again, I'm happy to try replacing the R316 resistor, but do you know is the left solder pad where the r316 resistor is, normally a ground point?
btw, I heard the r316 resistor is a 0 Ohm resistor.... what's the point of a 0 Ohm resistor?

Again, Thx so much :)

P.S. I didn't do the mod 'the way it was supposed to be done' because Tictac said

nah... no need to remove theresistor...
just solder a wire to that resistor
add in trimmer to the wire we just solder
and ground the other end... set resistance to max
and lower 5the resitance to increase vdimm voltage
measure vtt voltage to from pin 2 of dimm connector
just to make sure it still track 1/2 of vdimm voltage

so I figured it would work, and it did... it was my stupidity that ruined it :(

[Malves]

so I figured it would work, and it did... it was my stupidity that ruined it :(

So, now do it the way it was supposed to be done.;)

[Darien]

So, now do it the way it was supposed to be done.;)

errm... my stupidity was in the form of adjusting the voltage with the computer running... I got a voltage fluxuation when I did that, and that was what screwed up the mod... before that, the mod worked fine with many adjustments to it for one week...

did you have any other input regarding all the other questions I asked in my previous post?

[Malves]

I don't think that's a grounding point. Adjusting voltage with power on is fine. Never killed or damaged a board doing that.

Do the mod the way it is supposed to be done and see what happens.:)

[Darien]

I don't think that's a grounding point. Adjusting voltage with power on is fine. Never killed or damaged a board doing that.

Do the mod the way it is supposed to be done and see what happens.:)

Okie Dokie! :D

I already swung by Radio Shack and picked up some fixed 1K Ohm and 10 Ohm resistors... Radio Shack didn't have any SMD (Surface Mount Device) Resistors... but no biggie...

I'll doing the Mod tonight when I get home... I'll post the results

Thx again.

[Darien]

Very tough and trying, but victory at last Thank God

everything got far far more complicated than I will go into here...

but basically like the guide says, 0 ohms across the r316 solder pads is a zero increase, it's actually a decrease... if you remove the r316 resistor and short the solder pads (0 Ohms / no resistance) you will far below the voltage set in your BIOS, often too low to even POST into the BIOS... If you put maximum/too much resistance, remove the resistor altogether, or completly sever the line between the solder pads you will be stuck at maximum resistance...

the only plausable solution was to connect the two r316 solder Pads, with a VR Trimmer... I used a 1k 15turn trimmer.... this was insanely difficult... I won't even go into it... but unless you got mad crazy soldering skills, or have NO other choice (like me) don't do it this way...

Do it the way I did it the first time, but use the correct VR trimmer!!

just solder a wire to the r316 resistor, solder that wire to a 1K Ohm 15 turn (or more) VR trimmer, solder the second leg of the 1K Ohm 15 turn (or more) VR trimmer to a ground point.

MY MISTAKE: I believe what happened to the first mod I did... I used a 20k Ohm (instead of 1k Ohm) VR that probably had only 15 turns... not very sensitive (20 times less sensitive) and VERY easy to make a rapid voltage change... I believe this is what happened, I changed the voltage too quickly with the computer running and got a voltage fluxuation and it blew the r316 resistor... when this happened it somehow radically increased the resistance in the r316 resistor thus forcing my Vdimm to full throtle maximum... I've heard the R316 resistor is a 0 Ohm resistor, I don't think that's the case probably about a 300 Ohm resistor (guessing, it said 87A), but after it blew I removed it from the board and measured the resistance of the r316 resistor and it measured about 2k Ohms!!! I can get full throtle Vdimm with less that 1k Ohm resistance....

the trimmer you want to use for this mod is a 1k Ohm VR Trimmer with atleast 15 turns preferably 25 turns