motherboard cap question

[coreAngel]

Hi i need some help with some caps i have a motherboard which im recapping and im replacing the caps with panny fr's and united chemicon kya is that ok since one is low impedance and other is low esr?

[stj]

Re: motherboard cap question

impedence = esr

and FR's arent good enough to go around the cpu area.

[mariushm]

Re: motherboard cap question

At 100kHz or high frequencies commonly found in DC-DC converts on motherboards, impedance is pretty much equal to ESR.

FR are very low ESR but not really "designed" to be used on the VRM circuit (the dc-dc converter near the CPU). They'll work but ideally you should use better stuff, or polymer capacitors.
Perhaps if you mention the make and model of your motherboard and what you want to replace, maybe we can help.

[coreAngel]

Re: motherboard cap question

Thanks for the responses, i'm going to use panny fr around the vrm circuit and UCC KYA's on the rest ( i have plenty of cooling fans at the vrm area) it's not going to be over clocked and it's mostly intentioned as a spare pc so not much stuff going into it or a super gaming pc.

reason i asked is because on this motherboard all caps around the pc cpu area are Panny FL series 105 C the rest is some panny's a chemicon or two and the rest is a whole forest of Lelon (lecraps) small caps which im replacing with nichi's

[linuxguru]

Re: motherboard cap question

Panny FL doesn't fail easily unless there is a combination of heat *and* high ripple current, in which case it can bulge and spill some thick black goo. If they look OK, I'd leave all the FLs alone, and concentrate only on known bad cap series like KZG and KZJ. In a pinch, you can replace FL with FJ, but probably no other series from Panasonic.

[stj]

Re: motherboard cap question

well, MBZ,MCZ are discontinued, so i would use poly's

[ChaosLegionnaire]

Re: motherboard cap question

aye, just replace the lelon crap caps. dont replace the FL with FR. that would be replacing a "better" cap with a "lousier" cap at least esr/ripple wise.

[coreAngel]

Re: motherboard cap question

Ok the problem is some panny fl's failed, but not all only 5 failed im going to leave the rest intact there are many KZG caps which im going to replace, but i wanted to know if i can leave those 5 caps alone Panny FR's or should i switch?

[stj]

Re: motherboard cap question

depends, are the failed ones grouped with the good(visibly anyway) ones?

[coreAngel]

Re: motherboard cap question

depends, are the failed ones grouped with the good(visibly anyway) ones?

Yes those 5 caps they started bulging at the top the rest are fine. i don't know why?

[stj]

Re: motherboard cap question

a foto would help

[coreAngel]

Re: motherboard cap question

a foto would help

Sorry im currently searching for a new phone ( i have really bad battery life on mine) and i was only able to snap these two

[coreAngel]

Re: motherboard cap question

At 100kHz or high frequencies commonly found in DC-DC converts on motherboards, impedance is pretty much equal to ESR.

FR are very low ESR but not really "designed" to be used on the VRM circuit (the dc-dc converter near the CPU). They'll work but ideally you should use better stuff, or polymer capacitors.
Perhaps if you mention the make and model of your motherboard and what you want to replace, maybe we can help.

I posted pics, the motherboard came from a gateway system socket AM2 , motherboard is made by foxconn i scrapped the PSU it was dead (a bestec brand one)

[stj]

Re: motherboard cap question

did you already change some caps?
i see the gold writing FL's, but i also see white-text pana's - arent those FR?

[coreAngel]

Re: motherboard cap question

did you already change some caps?
i see the gold writing FL's, but i also see white-text pana's - arent those FR?

Yes i apologize i should have explained it correctly, yes i have replaced already some of the bulging caps with panasonic Fr's the rest are FL's and the rest i plan to replace are Chemicon Kzg's with KYA's and The Lecraps(lelon) with KYA's or low impedance nichicons

Unfortunately i didnt keep the bulging caps around i threw them away , what do you think should i leave the Fr's there? or remove them and replace them?

[coreAngel]

Re: motherboard cap question

Any feedback is appreciated.thanks

[stj]

Re: motherboard cap question

i'm not 100% sure, but from the foto i think the bad caps where on the 12v circuit - and probably killed by the psu

what are the voltage & capacitance of the ones you replaced, and the remaining FL's ?

[coreAngel]

Re: motherboard cap question

i'm not 100% sure, but from the foto i think the bad caps where on the 12v circuit - and probably killed by the psu

what are the voltage & capacitance of the ones you replaced, and the remaining FL's ?

the FR's i used to replace the bad caps were 16v 1000uf and the rest of the FL's are 6.3v 1800uf

[momaka]

Re: motherboard cap question

impedence = esr

Technically, not quite.
But at high switching frequencies (around 100 KHz), they are pretty close.

and FR's arent good enough to go around the cpu area.

Depends.

For the low side of the CPU VRM (i.e. CPU V_core), they *typically* are not good enough. This really depends on the board's vintage, though. This being a socket AM2 board, FR probably isn't fit for there but it *may* work (no guarantees if the caps won't be over-stressed or not, though).

For the high side of the CPU VRM (typically on the 12V rail), they may just be enough. But again, it depends on the board design. I have motherboards from around the same age use Chemicon KZE for the high side, and KZE is quite close to Panasonic FR spec-wise for certain cap sizes. Overall, though, the high side is not as stressed as the low side, so in many cases FR/KZE/ZL -class caps should be alright.

That said, you could also use larger-size FRs to get closer to the Panasonic FL and Chemicon KZG specs. Either higher voltage or higher capacitance (or both) a few notches.

i scrapped the PSU it was dead (a bestec brand one)

You should see which model it is. Only the Bestec ATX-250-12E is dangerous without modifications. The Bestec ATX-250-12Z, ATX-300-12E, and ATX-300-12Z are good power supplies after a recap. In fact, very good. They will do their labeled ratings all day long. People often dismiss the stock OEM PSUs in these big-company PCs as junk - and that's not the case. Delta, Lite-On, Newton, Astec, HiPro, and Bestec make some damn good PSUs.

[stj]

Re: motherboard cap question

the FR's i used to replace the bad caps were 16v 1000uf and the rest of the FL's are 6.3v 1800uf

not exactly what i meant.
i meant the ORIGINAL ratings.

but if your saying that all the bad FL's were 16v rated, and the remaining ones are all 6.3v then your done - the bad ones were on the 12v input, the good ones are on the VRM output.