Replacement for Rubycon 680uf 4v low profile?

[tinball]

Hello all,

New to the forums and thanks in advance for any advice you can offer.

I have been searching for a source / alternative capacitor model for replacing 3 Rubycon 680uf 4v MFZ series low profile capacitors. Does anyone have any suggestions?

On the Rubycon capacitor:
680uf
4v
MFZ

and

A0525
105 deg C
PET

These are from an Intel D101GGC board. They were located directly below the edge of the CPU heat sink which is why I need the same or similar low profile capacitors. They are approx 8mm cir X 8.5mm h.

I have not found specs on this particular capacitor besides what is on the capacitor itself.
The closest thing I have found in specs is a NCC 4V 680UF TMV Series Aluminum solid capacitors. (Tolerance -20 to 20, Impedence 20degC 100kHz, Ripple 100kHz).

However I have read nothing about whether it is safe or not to replace the Rubys with solid caps.

Again any help would be great.
Thanks,
James

[ratdude747]

Re: Replacement for Rubycon 680uf 4v low profile?

rubycon is a good brand. for them to fail you would have to have a heat issue. look to make sure all your fans are working so you dont kill the new ones

[tinball]

Re: Replacement for Rubycon 680uf 4v low profile?

Yes there was likely a heat issue with this board in that it was crammed under a desk with little ventilation. We have already replaced it for my client. I would like to try to replace it since it's a microATX form factor and look at playing around with it to perhaps make a MythTV box with it. That and the challenge of "can I do it?"

That said, I have not been able to find any specs on Rubycon's site regarding that particular series. Nor have I been able to find a replacement of around that height to use except the solid capacitor I mentioned in the first post. I'm wondering what my options are if I want to continue with this experiment.

I'm hoping someone can help.

Thanks

[gg1978]

Re: Replacement for Rubycon 680uf 4v low profile?

Polymers should work in VRM out on the board OK. General consensus on this forum is that you can usually put about 1/2 the capacitance in polymers, compared to regular electrolytics.. You'll probably want Sanyo Oscon SEPC's, or United Chemicon PSA's for that type of application.. 2.5V or 4 V polymers should be fine there. So for the 470's, i'd drop in some 220 or 330uF poly's instead.. Though you could probably put "full value" polymers in also..

How do the VRM input caps look?? (these are the ones that are typically by the 4 pin P4 power connector, and will be either 16 or 25V rated..

[kc8adu]

Re: Replacement for Rubycon 680uf 4v low profile?

i did one of those a while back.
used sanyo sepc 560@4.
filled the empty spots on vcore too.

[tinball]

Re: Replacement for Rubycon 680uf 4v low profile?

<gg1978 said>"Polymers should work in VRM out on the board OK. General consensus on this forum is that you can usually put about 1/2 the capacitance in polymers, compared to regular electrolytics.. You'll probably want Sanyo Oscon SEPC's, or United Chemicon PSA's for that type of application.. 2.5V or 4 V polymers should be fine there. So for the 470's, i'd drop in some 220 or 330uF poly's instead.. Though you could probably put "full value" polymers in also.."

I'm a bit slow on the uptake here so please be patient with me as I ask questions and learn more about capacitors.

So you're saying I should be fine with the solid caps (aluminum polymer I'm guessing) and that I can actually use a lower (around 50%) capacitance (uf) than the electrolytic caps that were originally on the board. So for the 680uf's I could go with a solid/polymer cap as low as 340uf?

Also regarding the voltage I could go with 2.5v? I'm curious since I've heard that you don't want to go lower in voltage. Higher is OK but lower is not.

If it makes any difference for application purposes, these Rubycon 680uf 4v caps are located directly above and just right of center of the CPU. They are labled as PCE21-23. The motherboard orientation would be CPU top-center-left, RAM to the right, backplane connections (VGA, serial, kb/mouse) on the left, and PCI-E bottom left.

"How do the VRM input caps look?? (these are the ones that are typically by the 4 pin P4 power connector, and will be either 16 or 25V rated.."

They look perfect - dead flat tops, vertical, no bulges. There is no vendor listed on them, black, 1000uf 16v.

There was also 1 other bad capacitor, it was a large 3300uf 16v capacitor. It's been removed and trashed so I can't tell you the specifics. I pulled the caps before coming to these forums and obtained a replacement locally - I should have waited I guess. I was located diagonally down and left of the cpu about 1 3/4 inches. It's labeled PCE43.

Thanks

[Per Hansson]

Re: Replacement for Rubycon 680uf 4v low profile?

Hi, I will leave your questions on polymers to someone like kc8adu that knows it better...

If this is a pic of your board then those caps are United Chemicon KZG series
http://cache-www.intel.com/cd/00/00/...828_243828.jpg
http://cache-www.intel.com/cd/00/00/...827_243827.jpg
http://www.intel.com/cd/channel/rese...les/243816.htm

As for the voltage, it is ok to decrease it, if (and only if!) you know what the circuit is rated for
Some examples; 10v caps can almost always be down rated to 6.3v because only 5v and 12v are normally found in a PC, therefore that 10v cap must have been on a 5v rail...

For the capacitors on the output side of the MOSFET for the CPU; These can always be decreased in voltage down to the vcore rating of the CPU
For a Socket 775 board like yours that means down to a minimum of 1.6v if you want to have support for all 775 processors made to date and allow no headroom for overclocking

[tinball]

Re: Replacement for Rubycon 680uf 4v low profile?

Per Hansson,

Thanks for the information regarding voltage. That makes sense and may help in getting this going. Especially with the lower profile caps around the CPU socket.

I'm hoping for some information regarding the solid caps since they appear the same size, capacitance, and voltage as the Rubycons.

The board you have in the links is the same board I'm using. However, the capacitors are different than in the picture. Colors are different. Sizes are about the same. The large 3300uf 6.3v cap below the CPU looks like it was the same but the rest are different. The caps around the 4 pin power connector are black with gold markings and a gold strip on the negative lead side. The small low profile "above" the cpu in the picture are actually black with grey markings (the Rubycons). Even the polymers left of the cpu are different. They have pink markings instead of the blue in the pics. I don't know if it makes a difference.