Asus ptgd-la

[2manybadcaps]

Hello everyone.

This will be my first recapping adventure. I have quite a lot of "practice boards" laying around and have been practicing desoldering, cleaning and soldering in a handful of random caps I grabbed from the local radio shack parts bin. Now im ready to recap a board that works but that I dont need so that I can test it, then (hopefully) on to a board that I do need to work...

So I have a ASUS PTGD-LA... Computer had a bad PSU (replaced) and now all these bad caps. Computer boots windows but is unstable then crashes. Removed mobo and found a couple VRM caps and several others are bulged and/or leaking electrolyte. I ordered a blue esr meter kit ( love to get new toys! ) but since its a kit and I have to wait for it I might not get to use it on this project (but I have plenty of other projects) so I decided to just replace all of the KZG caps on the board plus two others that I have yet to identify.

Here is what I have...
KZG:
3x 100uf 16v 5mmx10mm
3x 220uf 16v 6mmx10mm
1x 330uf 6.3v 6mmx10mm
2x 470uf 6.3v 6mmx10mm
11x 680 uf 4v 8mmX10mm
15x 820uf 6.3v 8mmx12mm
3x 1000uf 16v 8mmx20mm
2x 1500uf 6.3v 8mmx20mm

M?:
2 x 680uf 6.3v 10mmx10mm
These are yellow, marked -55*C-+105*C with a capital F above the temp rating (F has a horizontal line above and below it)
Other side of cap has an M with no parentheses and below the M is 5553U

This is what I could find in the BCN store:
100uf 16v 5mmx10mm Rubycon 100uf 25v 6x11mm ZLG
220uf 16v 6mmx10mm Rubycon 220uf 16v 6x10mm ZLH
330uf 6.3v 6mmx10mm Oscon 330uf 16v 10x13 SEP
470uf 6.3v 6mmx10mm Rubycon 470uf 10v 8x12 ZL
680 uf 4v 8mmX10mm Nichicon 680uf 16v 8x20 HZ
680uf 6.3v 10mmx10mm Nichicon 680uf 16v 8x20 HZ
820uf 6.3v 8mmx12mm Nichicon 820uf 6.3v 8x12 HN
1000uf 16v 8mmx20mm Nichicon 1000uf 16v 8x20 HN
1500uf 6.3v 8mmx20mm Nichicon 1500uf 10v 8x20 HZ

Now according to this thread...

https://www.badcaps.net/forum/showpo...7&postcount=88

... ZL and ZLH have a higher ESR value and SEP is not present so I assume I cannot use those. A few have different case diameters also. So other than those, will this selection of caps work? How much higher can the rated voltage be before having an effect on the circuit? Or does it ever?

I have ventured into the mouser and digikey catalogs only to have more questions. The 100uf 16v for example does not have a "low esr" or "low impedance" version but I did find a General Purpose PS series Nichicon. Unfortunately the ESR rating is blank. I have heard several people say that PS series are decent, so where do they fall in the order? But if this one works then should the Rubycon above not work as well even having a higher ESR value?

The KZG series is made by United Chemi-Con? I have read that they are an OK brand also, so is this just a bad series with so many ASUS boards having them and failing?

In looking for a spec sheet with the ripple current for the KZG series I found it (I think its attached to this post....) but am confused as to why none of the smaller caps have a value on the spec sheet. Do I just look for as high a ripple current as I can find? If I understand right, this will create less heat build up in the caps?

Sorry for so many questions and being so verbose. Its late, Im tired and rattling on so Ill stop for now and check back in tomorrow....

Thanks!

[Heihachi_73]

Re: Asus ptgd-la

The yellow 'F' caps are Fujitsu, which are a known good brand.

KZG caps are prone to failure in high temperature areas (such as around the CPU). Although some have been known to last for years, others have been no better than cheap Taiwanese caps in this aspect (e.g. Teapo or OST). The reverse can also be said, where cheap caps have lasted for years whilst others have failed after only one year.

Seems that you guys get the good caps compared to Australia! In our main stores (e.g. Jaycar), all we get are cheap and nasty S.I and Suntan brand caps.

[2manybadcaps]

Re: Asus ptgd-la

Thanks for identifying those Heihachi_73.

Sounds like about what happened here, the worst of the failed caps are around the CPU.

As far as the selection of parts goes I have not tried in years to buy anything locally. The only place I know of would be radio shack and frys electronics here in Phoenix, AZ. Neither EVER have what I'm looking for so I don't even bother. Even if I did find caps the right value/size I would not know if they were the correct specs (ESR / Ripple current) without looking them up anyway. I also just kind of assumed that they would be general purpose caps and not low ESR. But since were on the subject, does anyone know of a good electronics supply store in the phoenix, AZ area?