Abiy AV8 Vmods

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Originally Posted by HKY

I did the same thing with the same result, and 5 minutes ago I connected the other leg of the VR to ground and now the system won't boot up any more, even after I removed the ground. It stopped after "C1", (which means checking DRAM), and then return to "02" and then "C1" again and again. It can't even be turned off by the power on switch. The RAMs are OK because I checked them in another system.

I am afraid that either the motherboard (maybe the uGuru chip) or the memory controller of the CPU is dead.... I'll have to find another 939 board to check it out. Hopefully its the motherboard!

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Doh :(

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Originally Posted by Sampsa

Ok here is what I did:

http://www.io-tech.fi/pic/modit/av8_09_1.jpg

I removed the 0 ohm resistor which was attached to pin 7.

http://www.io-tech.fi/pic/modit/av8_10_1.jpg

http://www.io-tech.fi/pic/modit/av8_11_1.jpg

I replaced it with 1 kilo ohm VR and set it to 0 ohm.

Unfortunately Vtt didn't change when I raised the VR to 1000 ohms.

What next? Solder the other leg of VR to ground?

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So why would it help to solder the remmaining leg to ground?

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Originally Posted by Sampsa

Doh :(

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Its alright, Sampsa. The second I lay my soldering iron on the board I'm prepared to damage it. Just hope that the CPU is still OK.

Anyway check this out. I think this might work. (Keep trying man!)
http://xtremesystems.org/forums/showthread.php?t=38946

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Originally Posted by HKY

Anyway check this out. I think this might work. (Keep trying man!)
http://xtremesystems.org/forums/showthread.php?t=38946

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HKY, Hmm you have a VR with 2 or 3 legs? Just 2 legs and and you soldered the other to ground?

If I undestood correctly from the KV8-Pro Vtt thread, I should solder the remaining leg of my 3 leg VR to ground?

:)

The VTT mod works fine the way I did it:

http://www.vr-zone.com.sg/Shamino/av8/av8vtt.JPG

I never bother connecting to the other solder pad veside the pad cionnected to pin 7 but direct to the mosfet leg. 0 ohms and work up wards :)

I used a 3-legged 1K trimmer, similar to the one you used. I soldered the remaning leg to groud.

I've confirmed that the FX-93 is dead. Maybe I've damaged the memory controller. So it might bot be related to the vmod. I think you should do the mod without the CPU. Find the measure point on one of the legs of the MOSFETs around the DIMM and measured from there. That's what I did when I found the VDIMM mod. This time I was lazy because I want to read Vtt from BIOS and its a lot of work to remove and install the Mach2 - big mistake! (LA I wish you were here earlier!)

Ok Vtt-mod is working. I used the same method what Goldlocke used with KV8-Pro.

1. I removed 0 ohm resistor next to Winbond chip pin 7
2. I replaced it with 10 ohm resistor
3. I soldered 1 kilo ohm VR between 10 ohm resistor (the pad which is nearer Winbond chip) and GND

VR should be set to MAX and lowering the value will raise Vtt

I'm now installing Windows and I'll post the results later. Currently running Vmem 3,02 V and Vtt 1,51 V.

Thanks for your help everyone!

:toast:

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Originally Posted by Sampsa

Ok Vtt-mod is working. I used the same method what Goldlocke used with KV8-Pro.

1. I removed 0 ohm resistor next to Winbond chip pin 7
2. I replaced it with 10 ohm resistor
3. I soldered 1 kilo ohm VR between 10 ohm resistor (the pad which is nearer Winbond chip) and GND

VR should be set to MAX and lowering the value will raise Vtt

I'm now installing Windows and I'll post the results later. Currently running Vmem 3,02 V and Vtt 1,51 V.

Thanks for your help everyone!

:toast:

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:toast: Good to hear that! I'll do the same after I get another CPU! (Please show a photo for the completed work for easy reference for other users!)

Here is the picture of working Vtt-mod for Abit AV8:

http://www.io-tech.fi/pic/modit/av8_kaavio.jpg

http://www.io-tech.fi/pic/modit/av8_12_1.jpg

NOTICE! Remember to set VR to MAX (500 - 1000 ohms). Vtt will raise when you lower the VR value.

:toast:
:toast:

Unfortunately Vmem and Vtt mods didn't help much and 220 MHz FSB with tight memory settings is the best I can do. 225 MHz isn't stable even with 3,25 V to memory. I tried with Kingston KHX3500, Corsair 3200XL and Geil Ultra Platinum memories (all of them are BH5).

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Originally Posted by Sampsa

Unfortunately Vmem and Vtt mods didn't help much and 220 MHz FSB with tight memory settings is the best I can do. 225 MHz isn't stable even with 3,25 V to memory. I tried with Kingston KHX3500, Corsair 3200XL and Geil Ultra Platinum memories (all of them are BH5).

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That's strange! I can run at 250+ HTT with a paired of borrowed Geil Ultra-X at 2.5-3-3-10 before vmod so the motherboard should not be a problem. Have you tried increasing the chipset voltage?

Which 2 slots are you using? Also I think there are a couple of MOSFETs supplying VDIMM. Please measure the voltages of them to see if there is a difference.

Good job on getting this mod worked out guys. :up:

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Originally Posted by HKY

That's strange! I can run at 250+ HTT with a paired of borrowed Geil Ultra-X at 2.5-3-3-10 before vmod so the motherboard should not be a problem. Have you tried increasing the chipset voltage?

Which 2 slots are you using? Also I think there are a couple of MOSFETs supplying VDIMM. Please measure the voltages of them to see if there is a difference.

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Well 2.5-3-3-10 memorysettings aren't actually what I'm looking for.

I'm trying to run at 2-2-2-5-7-12 :)

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Originally Posted by Sampsa

Well 2.5-3-3-10 memorysettings aren't actually what I'm looking for.

I'm trying to run at 2-2-2-5-7-12 :)

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I know we are all aiming at 2-2-2-5 with out ol'BH-5s. That's why we are trying to Vmod it. I am just saying that the motherboard should have no problem running at 250+ HTT, so I found it strange that the VMOD didn't help your RAMs to run t least in the 240s. Too bad I don't have a 939 now so I can' test it. I'll probably wait until November to buy a new one, as AMD should reduce the prices then.

Sampsa VTT way works perfect for me, but Vdimm mod mention on this thread cause me major drops under loads and reduced constantly. I did it this way and I m running with it right now. Far more accurate and is rock stable under load (memtest#5) w/ one dimm@3.3 and has a little drop (compared to previews way) w/ DC setup (2x512) 3.26 under load when idle 3.3. :)
(this is actually Hipro5 way on IC7 :toast: )

http://www.xtremesystems.org/forums/...chmentid=18491

note: I also removed R 87A from first pad (it was around 760 ohm and it was grounding, I don't now if it's necessary to do so, but I just mention it)
And cut only the trace! is a small one sorting the 2 points the R that I placed, u shall see it w/ naked eye (or a magnifier glass)

could anybody write a collection of all those mods (with pictures and detailled descriptions of course...)??????????????????

VagpSen is Pin34 track the trace down to find out how it can be done.
Maybe I search for it but not this week.
But what do u want it for above 1.65?
The bigger problem on this mobo is that oc the ΒΗ-5/6 like crap no matter the volts u feed it :(
http://www.xtremesystems.org/forums/...chmentid=19922

I have a following problem. Contact platforms of the resistor r84 have come off. I need find out where there are contacts of this resistor to return it back.