Biostar P4M900-M4

[Colt45ws]

This board was never really stable, and lately it has gotten worse. I open it up regularly and check it over and have not seen anything up to now.
One of the KZGs on the VRM input has popped.
Im going to recap the the whole board 470uf and up as with the exception of the UCCs on the VRM it is covered in OST.
I think I have decided on this list of replacement caps. I was largely limited by what was in stock at mouser since digikey didnt appear to have any capacitors that could match the KZGs. I ended up with a series or two better than what was needed to match the spec of the originals.
4x 3300uf 6.3v 10x25mm nichicon HZ was UCC KZG
3x 1500uf 16v 10x20mm nichicon HZ was UCC KZG
13x 1000uf 6.3v 8x11.5mm nichicon HM was OST RLP
1x 470uf 16v 8x15mm panasonic FM was OST RLX

[Colt45ws]

Re: Biostar P4M900-M4

Ended up ordering from two places which I didnt want to do, but everyone seems to be out of everything for some reason?
This is what I got.
4x 3300uf 6.3v 10x25mm Rubycon MBZ was UCC KZG
3x 1500uf 16v 10x20mm Rubycon MCZ was UCC KZG
13x 1000uf 6.3v 8x15mm nichicon HE was OST RLP
1x 470uf 16v 8x15mm panasonic FM was OST RLX

[Colt45ws]

Re: Biostar P4M900-M4

I decided to do a slight poly mod on this. The VRM out will be getting 4x nichicon FPCAP R7 2.5v 1500uF instead.

[weirdlookinguy]

Re: Biostar P4M900-M4

Let us know how this goes. I am curious as to whether the new caps will solve the stability problems you say the board has always had.

[Colt45ws]

Re: Biostar P4M900-M4

Pulled the board to desolder the caps. The VRM are is getting SMOKING hot. The bottom of the board is turning black and you can see colors in the solder lines. Its not surprising that top one failed first, its right in the middle of two hot spots.

[Colt45ws]

Re: Biostar P4M900-M4



http://colt45.ws/misc/p4m900kzg.jpg
Popped one was right between two hot spots. I had a 2 month old case fan fail; locked up tight. It was right after that I noticed it had popped. Coincidence? I think not.

[Colt45ws]

Re: Biostar P4M900-M4

http://colt45.ws/misc/p4m900done.jpg
Dropped it back in. Plugged it in to minimal accessories, and it fired right up.
Its funny, it does not look like I did anything with the rest of the board. Because the nichicon HEs have the same color scheme and vent stamp as the OST garbage they replaced.
Running a Prime95 burn in. Also I turned on the 'top performance' BIOS option just for shits and giggles.. Even when this board was new it wouldnt run with that option enabled. Curious if a set of quality caps will change that.

[Colt45ws]

Re: Biostar P4M900-M4

*giggle snort*
After about 20 minutes of run time, I heard a sound not unlike someone opening a can of liquid refreshment. I turned around and the machine was off. Dead and wouldnt come on.
I checked the board over, thinking I messed up and it shorted out; couldnt find anything.
So I went on to test the power supply. Plugged it in and checked for 5VSB. Nope. UhOh. I think we have our culprit. I shutdown one of my other machines and ganked its power supply. The newly recapped board fired right up on it.
Thats a project for tomorrow. I opened it but I dont see anything obviously wrong like a short or similar, but I have not checked real carefully.

[Toasty]

Re: Biostar P4M900-M4

Nice job! Like the poly-mod.

KZG (and KZJ) are -known- high temp failures.

Looks like you've had some heating of the MOSFETs nearest the CPU. The cap popping probably saved you much aggravation.

Better to use the "Go Advanced" button and choose the "Manage Attachments" button there to upload pics. You can do it direct from your computer, or use the "Upload File from a URL" section, and do it from your site. That way the pics are -always- here for future reference. If "colt45.ws" were to go away, your pictures will go too.

Toast

[Colt45ws]

Re: Biostar P4M900-M4

Oh, good idea. Im just used to tossing it up on my server.
Ill attach them here, just in case.

[Colt45ws]

Re: Biostar P4M900-M4

Board completed 48 hours memtest and 48hours prime95 2 thread 8-256K in place FFT. No problems.

[Colt45ws]

Re: Biostar P4M900-M4

The VRM area still got quite hot as far as I was concerned. So I was looking on newegg when I found these cute little heatsinks made for putting on mosfets. I bought a pack when I bought a new power supply, a Seasonic S12II 520W.
I installed them with some Arctic Silver thermal epoxy. I think they are too small to be ultra effective, but every little bit helps and these are about as big as you can go, with the way the VRM is designed with the mosfets all over the place, in between coils and caps.

[cdoublejj]

Re: Biostar P4M900-M4

you need these . . .

http://www.newegg.com/Product/Produc...82E16835708011

also if you could stick a really thick thermal pad (like those used on the vram on the xbox 360) right in between VRM area and the computer case it would really help. it would cool it off a good amount with those heat sinks alone.

also i volt modded a p4p800 not too long ago that was having stability issues ran prime 95 and not to long and a POP smoked the PSU big time the smell of burning plastic and electronics filled the room i shoved piece of crap PSU in there again it runs fine but, it made that burning electronics smell for a while.