Replacement for Rubycon MCZ Caps ??

[Pipkin]

Hi,

I'm needing to replace some caps on a motherboard from our Dell Server.

It's about 10yrs old, and initially I thought it was going to be one of those 'capacitor plague' issues that I read Dell had problems with.

But... on closer inspection, I find that Dell had used Rubycon MCZ caps on the board, which after reading on this forum, I understand are deemed to be 'GOOD' caps ?

So I'm guessing it's just the age of the cap that has been the problem. The server will have been on 24/7 for the best part of ten years, so I can't complain !

Anyway - can anyone suggest a suitable replacement for the following caps please ?? As I understand that Rubycon have stopped making the MCZ series ? I found some on ebay, but I'm worried they are either fake, or old stock ?

Rubycon MCZ 16V 1000uF ( MB has 4 of)
Rubycon MCZ 6.3V 2200uF ( MB has 31 of)
Rubycon MCZ 6.3V 1800uF ( MB has 14 of)
Rubycon MCZ 6.3V 1500uF ( MB has 2 of)
Rubycon ZL 6.3V 220uF ( MB has 4 of)
Rubycon YK 16V 220uF ( MB has 2 of)

The only caps showing physical signs of failure are the 2200 & 1800 devices. About 8 of these are 'gone'. Do you generally replace all the caps including the OK looking ones ?

I had a look on farnell, and searching for Rubycon 6.3V 2000uF returned the following ...

ZLH Series
ZL Series
YXG Series
YXF Series

Would any of these be OK ?

Many Thanks to you all

[stj]

Re: Replacement for Rubycon MCZ Caps ??

mcz are some of the best, i would only replace them with poly's

[Pipkin]

Re: Replacement for Rubycon MCZ Caps ??

mcz are some of the best, i would only replace them with poly's

OK .....

So can you point me in the direction of a suitable 'poly' series I should be looking at ?

Thanks for your help

[retiredcaps]

Re: Replacement for Rubycon MCZ Caps ??

Hi,
But... on closer inspection, I find that Dell had used Rubycon MCZ caps on the board, which after reading on this forum, I understand are deemed to be 'GOOD' caps ?

Rubycon MCZ are good caps.

Running 10 years at 24x7 = 87,600 hours.

See this post

https://www.badcaps.net/forum/showpo...4&postcount=10

So if your server was running around 55C internally, the MCZ cap life would be around 64,000 hours.

[Pipkin]

Re: Replacement for Rubycon MCZ Caps ??

Rubycon MCZ are good caps.

Running 10 years at 24x7 = 87,600 hours.

See this post

https://www.badcaps.net/forum/showpo...4&postcount=10

So if your server was running around 55C internally, the MCZ cap life would be around 64,000 hours.

Thanks for that info. It's good to know that Dell didn't cut corners with the caps then - it might explain why the server cost so much more than a PC does !

So that leads me to the question of replacement... Are the MCZ caps still available, and if so, where can I get hold of some genuine ones ?

Or... have Rubycon replaced them with an improved series ?

[Per Hansson]

Re: Replacement for Rubycon MCZ Caps ??

No, all these highend electrolytic caps have been replaced in new designs with solid polymer caps, and thus the large manufacturers have stopped manufacturing electrolytics with ultra low ESR.
The reason you see such high capacitance rating in most VRM designs is because the larger the cap the lower it's ESR is, and that is what the board designer is after.
A high frequency VRM does not need allot of capacitance, due to it's high switching speed what it needs is ultra low ESR.
Thus it is fine to replace the caps with polymers of significantly lower capacitance.
But we need to see where they are used, because this only applies to the kind of regulators I have described.
Can you post some pics of the board, I'm guessing there are allot of caps but only those in high-stress VRM positions will have failed...

https://www.badcaps.net/forum/showthread.php?t=13542
https://www.badcaps.net/forum/showthread.php?t=21540

[retiredcaps]

Re: Replacement for Rubycon MCZ Caps ??

Are the MCZ caps still available, and if so, where can I get hold of some genuine ones ?

MCZ was discontinued back in 2010. I believe Nichicon HZ meets or exceeds the ripple and ESR specs of the MCZ. You can compare yourself using the datasheets linked below.

http://www.thecapking.com/spforrumcz.html

Badcaps store sells Nichicon HZ.

https://www.badcaps.net/pages.php?vid=23

[Pipkin]

Re: Replacement for Rubycon MCZ Caps ??

Thanks for all your help :-)

I've taken the server apart again, and snapped a few photos.

I've also done an 'overview' shot and then highlighted the eight caps which have obviously gone.

Any advice greatly received ...

[retiredcaps]

Re: Replacement for Rubycon MCZ Caps ??

I've also done an 'overview' shot and then highlighted the eight caps which have obviously gone.

Unless you have an ESR meter to test the remaining non MCZ bloated caps, I would say the remaining caps are suspect.

Unless you have an absolute need to put this motherboard/server back into service, you might be better off getting a replacement?

[mariushm]

Re: Replacement for Rubycon MCZ Caps ??

Those by the cpu sockets you could replace with polymer capacitors rated for 4v... the actual voltages are much lower in reality so that would be perfectly fine.
You can probably use 1500uF 4v capacitors instead of the 2200uF ones and 1000-1200uF ones instead of the 1800uF capacitors.

Those capacitors by the chipset and other locations further away from the cpu sockets, you can go with series of capacitors that are close enough to the old Rubycon series, the motherboard won't be that picky about what you use.

[stj]

Re: Replacement for Rubycon MCZ Caps ??

seems a waste only half-loading it, get a second cpu!

[Pipkin]

Re: Replacement for Rubycon MCZ Caps ??

Unless you have an ESR meter to test the remaining non MCZ bloated caps, I would say the remaining caps are suspect.

Unless you have an absolute need to put this motherboard/server back into service, you might be better off getting a replacement?

We need to have this server in operation at the moment. It is running with the caps as they are now - we spotted them during a routine clean of the server today.

I want to do something about them, before they become a bigger problem - hence why I'm looking for replacements.

[Pipkin]

Re: Replacement for Rubycon MCZ Caps ??

seems a waste only half-loading it, get a second cpu!

And load up the already stretched power supply some more ??

[Pipkin]

Re: Replacement for Rubycon MCZ Caps ??

Those by the cpu sockets you could replace with polymer capacitors rated for 4v... the actual voltages are much lower in reality so that would be perfectly fine.
You can probably use 1500uF 4v capacitors instead of the 2200uF ones and 1000-1200uF ones instead of the 1800uF capacitors.

Those capacitors by the chipset and other locations further away from the cpu sockets, you can go with series of capacitors that are close enough to the old Rubycon series, the motherboard won't be that picky about what you use.

So I should be OK to use 'Nichicon HZ' for the ones not near the CPU socket ?

What series of polymer caps should I be looking at for the CPU ones ?

I haven't used polymer caps before.

Thanks

[stj]

Re: Replacement for Rubycon MCZ Caps ??

you may want to check the caps in the psu.
a good excuse to blow the dust out of it.