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Old 09-14-2020, 01:59 PM   #1
hansy
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Default Replacement Chemicon SMG caps

Hi All,

Ive just pulled apart a bowers & wilkins sub.
The power board is covered in crappy chemi con SMG series caps. A couple are leaking and some others have ESR levels above manufacturer spec.

Please any advice would be dearly appreciated. I want an alternative at least 105degrees longer life caps (the smg are 85 degrees 2000hrs)
Ive been reading and getting more confused, ppl saying you need to match the same ESR and spec correctly.

Ive attached pics - the little black caps are the SmG - not sure if i need low esr caps or general purpose etc
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File Type: jpg F4F4F167-D32F-4280-8B67-F6A7988F7720.jpg (379.7 KB, 34 views)
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Old 09-14-2020, 03:27 PM   #2
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Default Re: Replacement Chemicon SMG caps

None of those *appear* bad. As far as leakage, if you're referring to the white stuff around the bases of the larger ones, that's not leakage....it's glue.

As a rule, UCC caps are pretty good, their only 'troublesome' series were KZG and KZJ.
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Old 09-14-2020, 03:48 PM   #3
hansy
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Default Re: Replacement Chemicon SMG caps

Ive tested all of the caps and a number are faulty.
My main thing is a recommendation of which series of cap to go for in a brand like panasonic, nichicon, rubycon
( with at least 105 degrees and longer lifespan)
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Old 09-14-2020, 04:37 PM   #4
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Default Re: Replacement Chemicon SMG caps

i tend to just put panasonic FR in just about anything these days
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Old 09-14-2020, 05:01 PM   #5
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Default Re: Replacement Chemicon SMG caps

Quote:
Originally Posted by stj View Post
i tend to just put panasonic FR in just about anything these days
I approve this message.
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Old 09-14-2020, 05:38 PM   #6
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Default Re: Replacement Chemicon SMG caps

Quote:
Originally Posted by stj View Post
i tend to just put panasonic FR in just about anything these days
Thank you! Ill order some panasonic FR series for the recap (will there be any issues given that they are low esr?
Anyone have any experience with the Panasonic EEUTA1 they are rated at an insane 125 degrees!
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Old 09-15-2020, 02:46 AM   #7
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Default Re: Replacement Chemicon SMG caps

philips make 135degree caps,
i dont think the esr and ripple are good on the really high temp stuff though - they are generally intended for stuff like gas ignitor units.
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Old 09-15-2020, 05:20 PM   #8
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Default Re: Replacement Chemicon SMG caps

SMG is UCC/NCC's general purpose series, not low quality. And it looks to me like they are being used appropriately.

That said, just about any of the good brands' non-aqueous low impedance series should do well:

UCC/NCC LXZ series

Panasonic FC series (is FR the newer non-aqueous low impedance series?)

Nichicon PW or PA series

Rubycon YXF

These brands' long-life aqueous series are all excellent, but aqueous parts tolerate ambient heat a little less well, and these series' lower impedance is of no special benefit.

So go with best price and availability of the series listed above, IMO.
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Old 09-24-2020, 06:15 PM   #9
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Default Re: Replacement Chemicon SMG caps

Quote:
Originally Posted by PeteS in CA View Post
SMG is UCC/NCC's general purpose series, not low quality. And it looks to me like they are being used appropriately.

That said, just about any of the good brands' non-aqueous low impedance series should do well:

UCC/NCC LXZ series

Panasonic FC series (is FR the newer non-aqueous low impedance series?)

Nichicon PW or PA series

Rubycon YXF

These brands' long-life aqueous series are all excellent, but aqueous parts tolerate ambient heat a little less well, and these series' lower impedance is of no special benefit.

So go with best price and availability of the series listed above, IMO.
FR is an aqueous series AFAIK, similar specs to HE. All very good caps. Since this amp used SMG, I would preferably stick with the same class of caps, but using higher temperature variants. KMG, NHG and VZ would be most appropriate choices for the intended design.

Last edited by pc7fan; 09-24-2020 at 06:18 PM..
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Old 11-19-2020, 06:30 PM   #10
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Default Re: Replacement Chemicon SMG caps

Quote:
Originally Posted by PeteS in CA View Post
SMG is UCC/NCC's general purpose series, not low quality. And it looks to me like they are being used appropriately.

That said, just about any of the good brands' non-aqueous low impedance series should do well:

UCC/NCC LXZ series

Panasonic FC series (is FR the newer non-aqueous low impedance series?)

Nichicon PW or PA series

Rubycon YXF

These brands' long-life aqueous series are all excellent, but aqueous parts tolerate ambient heat a little less well, and these series' lower impedance is of no special benefit.

So go with best price and availability of the series listed above, IMO.
My neighbour has a friend who is willing to replace all of my caps free of charge with Rubycons YXG series caps (they are the only ones they have at his work). My apologies as I am a complete noob - and cannot fully understand the data sheets of the caps.

smg specs:
https://www.digikey.com/catalog/en/p...mg-series/3646

rubicon:
https://www.digikey.com/catalog/en/p...g-series/25454

the high and low frequency ripple currents appear to have significant differences in values between the SMG and YXG caps. Will it be an issue with stability or cause any issues if I replace all of the smg caps for the rubycon yxg?

(its for a b&w subwoofer power board and amp board both of which are covered with chemi con SMG caps, 3 of which are faulty) - both the smg yxg are labelled as general purpose.

thank you all for your kind patience

Last edited by hansy; 11-19-2020 at 07:20 PM.. Reason: more detail
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Old 11-19-2020, 08:38 PM   #11
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Default Re: Replacement Chemicon SMG caps

You will probably alright using them ( this would not be my first choice but might be a third choice but it cost that drive my choice ) my first choice is United Chemi-Con KY / KZE / LXZ or second choice FR / FC ( size diameter and height make this choice for me sometime ) I find that this brand of capacitor are higher in cost. The smaller UF under 100 UF value of capacitor I buy a hundred of them at a time

Sometimes it what device I am working on and what brand of capacitor are already installed sometimes make that decision for me if I can still find that series or not

Some Servo motor controller can be pick-e what type of capacitor that is used
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Last edited by sam_sam_sam; 11-19-2020 at 08:57 PM..
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Old 11-21-2020, 01:45 AM   #12
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Default Re: Replacement Chemicon SMG caps

Quote:
Originally Posted by hansy View Post
My neighbour has a friend who is willing to replace all of my caps free of charge with Rubycons YXG series caps (they are the only ones they have at his work). My apologies as I am a complete noob - and cannot fully understand the data sheets of the caps.

smg specs:
https://www.digikey.com/catalog/en/p...mg-series/3646

rubicon:
https://www.digikey.com/catalog/en/p...g-series/25454

the high and low frequency ripple currents appear to have significant differences in values between the SMG and YXG caps. Will it be an issue with stability or cause any issues if I replace all of the smg caps for the rubycon yxg?
Should be fine.
I see that the picture of the PSU you showed is of the switching type. So if anything, YXG will probably do better than SMG due to having lower ESR... and also longer rated life.
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