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ASUS P5K Capacitor Mod

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Perk

Registered
Joined
Nov 26, 2008
Location
England
I have got the camera, will upload what I hope is some clear enough pictures in a while.

I took heatsinks off the MOSFETs that I had thermal padded on, as they were in the way of taking clear photos.
Decided to leave them off after re-installing the CPU HS. Will put them back after the new caps are fitted.

I thought I would have another go at an overclock, to see how hot that area got without HS's there.
At 3700nhz 1.44vcore, the (CPU MOSFETs?) reached 158c. I couldn't find any info regarding max operating temps for them, I thought I had read somewhere 155c was the limit, but could be very wrong about that.
I didn't use a DMM on the Vcore, but if you look at the Speedfan voltage you can see how it's jumped about quite a bit. (vdroop pencil mod in place)


Edit: After some more testing using Intel Burntest, it looks like I get the same results with voltage, when running anything around 3.6ghz. Max stable voltage I can use is 1.38volts, after that it just drops voltage down(even with pencil mod) and thus fails stability tests.

Edit2: More testing with a DMM for vcore readings- Intel Burn Test set to run x10
450x8 - Vcore set at 1.45v in bios- reads 1.445 in windows, running IBT, lowest voltage was 1.406v=Passed test
463x8 - Vcore set at 1.465v in bios reads 1.465v in windows, after running IBT, lowest recorded voltage was 1.405v=Failed test
Maximum emperatures stayed around the same(under 70c). So I assume it's the voltage drop that is causing the failures.
Also thinking my vdroop pencil mod has stopped working and needs reapplying.

Edit3: Reapplied vdroop, and tested again. When testing @ 3700mhz(bios set at 1.45v/ real vore 1.465v DMM), vcore drops to 1.416v under heavy load, and flashed 1.3volts just before pc rebooted itself.

One thing I have really noticed(which have read many times before though) is how useless it is using voltage monitors in windows. They really have no relation to what voltage the CPU is getting at any given time. At a lower stable overclock the CPU voltage stayed completely stable on the DMM, where speedfan showed massive fluctuations.
I monitored temperature of the MOSFETS next to the CPU and as they reach higher temps the voltage does seem to drop more and more. With the PC case open then reached 146c, with it closed 155c.
I wonder am I flogging a dead horse trying to mod this board in hopes of better voltage stability?

Would this cap mod help this vcore stability issue, or is it really just to save cap damage? I imagine its the latter, and it's the 3 phase power that's to blame.
 
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Perk

Registered
Joined
Nov 26, 2008
Location
England
Tried to get one pic that had all the places where you suggest to fit caps.
Is this ok for you to mark which caps goes where?
I have other pics if needed.
Edit: ordered 2 of each of the parts you listed above. I could not see all the places you have added Caps to, so hopefully that is enough of each.
Can always order more once you've posted what goes where. Still need to get some new solder and new tip for my soldering iron, as the current one has seen better days.


 
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Perk

Registered
Joined
Nov 26, 2008
Location
England
Hehe np's I'm in no rush.
I knew it was Thanks Giving, thought you might be busy anyway :)
 

nightelph

Member
Joined
Sep 28, 2004
You won't see any bulging caps. The stock ones are pretty good (Fujitsu). It is just that all locations are not populated. Usually, I'd like to fill up the CPU VRM and DRAM sides. :)

Just ran into this thread. I've got a P5K premium but I'm going to check for blank spots to fill up with caps. I don't have a quad yet, but this rig will be my main for another couple years until Sandy Bridge comes out. I'll probably have a quad by then.
 

Perk

Registered
Joined
Nov 26, 2008
Location
England
Will be pretty busy over next few weeks, so I'll leave this mod until after the xmas now.
Have a good christmas :beer::santa2:
 

Quade13

New Member
Joined
Feb 4, 2017
I'm sincerely sorry to bump this ancient, obsolete thread.
There are a couple of questions to Super Nade, I know it's fairly late to respond, but hoping you will notice this one brought up to attention.
Got an ASUS P5KR board, which is similar to the baseline version of the P5K, with the only exception to the updated southbridge that got RAID support hooked up. The entire CPU power caps array got aged out well and no more functioning at all, and given how I grew up on this board, willing to revive it and throw the Q6700 at 4ghz I had back in and utilize this computer as a backup option. The other caps seem to be up and running, although they require further measurements. The power transistors didn't get a hit, but the 4pin CPU socket got as black as charcoal due to a nasty OC story I've recently had with a faulty PSU and a dual GPU card on top of that. The board is booting up, works fine, but fails miserably at times on load due to the caps. Can't give up on it, it used to do a decent overclock and 500+ FSB on dual cores.

So it goes to Mr. Super Nade, is there any chance you look up your archives and refresh your memory on the cap mod? Specifically, can you please provide a set of caps to be replaced in the first place (besides the ones that are already dead on this mobo), preferably picturized. I can't seem to find top tier caps locally, so most likely the only place to grab some will be aliexpress or some folks in town. I've read through the discussion, but the info on this is quite old.
I'll appreciate if anyone directs Nade to this thread.
 

Quade13

New Member
Joined
Feb 4, 2017
Hey, Mr.Scott
Unfortunately, they don't ship it to my region. I've found a couple of local sellers for the replacement, but another issue has arisen. It appears that one mosfet seems to be dead on the third phase, 12v CPU > this mosfet indicates a short in the circuit. Possibly a candidate for a replacement, luckily NIKOS fets are commonly found and available. The board boots up, logs into OS, but is unstable. No wonder, actually, with the caps and one faulty mosfet. The fried 12v connector looks healthy and outputs stable 12v, it's just the needles dimmed black, although I am still concerned with the conductivity. So yeah, more troubles than I anticipated.

I was looking for the caps I can reinforce the ATX 24pin with, as well as northbridge area, and possibly an extra cap for the 4pin CPU. I can replace the existing ones, Nade mentioned additional caps that can be installed to provide stability and I am not sure which. Any idea?

A pro tip for other folks attempting at overclocking this board: don't do C2Q's over 1.5v and overload your 12v rail. EP45-UD3 (non L) and Biostar i45 are the way to utilize such a huge load (and superior P5Q boards).
 
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OP
Super Nade

Super Nade

† SU(3) Moderator  †
Joined
Aug 30, 2004
Location
Santa Barbara, CA
Quade13,

Would you mind posting a couple of pictures of your board, especially the areas with damage? The first thing to remember is to use capacitors of the same or higher voltage (see my signature for a MB repair tutorial). You can use lower voltage caps in certain places such as the CPU VRM area, but best not to do it. Do you have access to ebay? Where do you live?

Edit: Post in my sig: http://www.overclockers.com/recapping-an-epox-8kra2/