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Old 28th August 2008, 10:28 AM   #1
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Default Information on B41840 Epcos caps

I bought some of these:

http://www.tedss.com/B41840-A9688-M

The model number is B41840-A9688-M

But I can't seem to find any specs or datasheets on them, even on the Epcos site. Why is this?
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Old 29th August 2008, 04:21 PM   #2
KSTR is offline KSTR  Germany
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This looks suspicious, those caps show up (googling the model series number) mostly as ebay and HiFi-parts dealer items, and only the 6800uF/100V model. They might all come from the same batch of fakes....

Do you have means to safely(i) measure them during or after reforming, that is capacitance and leakage current?

Or just dismantle one, sometimes there is the original cap's sleeve still under the second layer of shrink tubing. There even have been horrible pics around on the net of fakes that contain a way smaller cap inside, just like a russian babuschka puppet. Do they sound hollow when you hit them with a pencil?

- Klaus
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Old 29th August 2008, 05:29 PM   #3
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Well I ordered them from the US and they still have not arrived yet. Once they arrive I'll dismantle one to see if it's a fake... I've also e-mailed the shop requesting a datasheet - hopefully they'll send one.

I was thinking it could be an old model that Epcos no longer make, but they claim that the caps are new, so rules that out.

I also have a multimeter with a capacitance function, so I'll be able to check that they are 6800uF... I don't really have anyway to test leakage current tho, I only bought them to replace some caps that have gone bad in an existsing amp.

Would it be safe to just try using them in the amp or would I damage it somehow?
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Old 29th August 2008, 07:24 PM   #4
KSTR is offline KSTR  Germany
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If those are fakes, especially with a lower voltage rating (which is likely as 100V types are pretty rare), they could explode right on the first switch-on, and probably causing more servere damage to the amp (let alone the mess when the caps spit out their agressive guts -- acids -- all over inside the amp).

Cap value readings from multimeters are to be taken with care, further, electrolytics are often rated -20%...+50% and when they have been sitting in a store or wherever for maybe years the values can drift even further (to the low side).

You might want to take a look this EPCOS paper on these caps in general, and on leakage current and forming in detail (topics 3.7 ff, pgs.15 ff). Point is, you apply a current limited(!) increasing DC voltage up to the spec'd voltage and monitor the DC current through the cap, looking for abnormal high values and/or the point at which it skyrockets. Use safety glasses! The only way of knowing of what the expected values would be is to either have a "known good" cap of similar specs (general type, uFs, voltage and volume) and measure it or at least look at the datasheet to get a clue. Which is a problem, in the whole snap-in series currently on the EPCOS site there is no 6800uF/100V -- which might want to tell us something... as I said, 100 Volters are pretty rare stuff. The one I found (screw terminals, economist standard model B4145*), are 35mm dia X 105mm height, which again tells us something...

- Klaus
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Old 29th August 2008, 10:26 PM   #5
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Well I do have a single Rubycon USR 100v 6800uF capacitor which is 35mm x 50mm, so I can compare the Epcos caps against that. I know it isn't ideal but it should be better than nothing. I wish I could have got more Rubycon's but nobody seems to have them in 100v 6800uF 35mm x 50mm now.

I do have some +-45V toroids tho, so I could pick up a bridge rectifier and see if they are good for ~60V at least...

I also have some +-30V toroids, so I could even bridge the centre tap and have to cap go from the -ve rail to the +ve which should give around 85V to the cap.

Also this amp is a PA amp so I can take the PCB which holds the caps out of the chassis (and disconnect it from the rest of the amp) so if they do go bang the damage will be minimal... I'll be sure to keep it away from the transformer also. Would it be worth using some sort of dummy load when I have the rest of the amp disconnected?

Also my e-mail to the shop bounced, not a good sign... I'll try ringing them when they are open...
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Old 29th October 2008, 09:32 AM   #6
clm811 is offline clm811  United States
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Default Any updates?

Mike,

Did you ever get those 100v Epcos caps, and are they ok, or "fakes" as some have suggested?? I was thinking of picking up some myself.

-chas

Quote:
Epcos caps...The model number is B41840-A9688-M
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Old 22nd January 2009, 04:42 PM   #7
emilvv is offline emilvv  Bulgaria
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Default need some info .. please help

Hello,
I bought some caps from TEDSS.COM but without any track number .. info or reply from support .... (( Do you receive your caps from TEDSS.COM ... ??
Please write me at emilvv@gmail.com ... or skype - emilvv

Thanks in advance !!

Emil
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Old 23rd February 2009, 06:39 PM   #8
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Default B41840-A9688-M

check out http://app.arrownac.com/aws/pg_webc/...8S6949815N9769
Perhaps is some evidence that those caps existed somewhere, sometime.

NNSO (new not-so-old stock)

I have the 10.000 uF equivalent in the PSU of a 100w amp, going strong since 2006. Surprisingly good.

Apparently, origin is (or was, because those things are changing constantly) Epcos Brazil. I donīt know if the factory still exists. Maybe China now, or Hyperborea....

Welcome to the globalized world!
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Old 24th February 2009, 12:21 AM   #9
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Default Re: B41840-A9688-M

Hey guys, sorry for not replying sooner, this thread dropped off my radar...
Quote:
Originally posted by clm811
Mike,

Did you ever get those 100v Epcos caps, and are they ok, or "fakes" as some have suggested?? I was thinking of picking up some myself.

-chas

Yep, they arrived fine, I tested then out of circuit and they seemed ok. Installed them in the amp and the amp works great. They don't look fake to me but I could be wrong.
Quote:
Originally posted by emilvv
[B]Hello,
I bought some caps from TEDSS.COM but without any track number .. info or reply from support .... (( Do you receive your caps from TEDSS.COM ... ??
Hi, yes mine turned up fine, I don't think they sent me a tracking number, and they took over a week to arrive from what I remember.
Quote:
Originally posted by federico moreno
check out http://app.arrownac.com/aws/pg_webc/...8S6949815N9769
Perhaps is some evidence that those caps existed somewhere, sometime.

NNSO (new not-so-old stock)

I have the 10.000 uF equivalent in the PSU of a 100w amp, going strong since 2006. Surprisingly good.

Apparently, origin is (or was, because those things are changing constantly) Epcos Brazil. I donīt know if the factory still exists. Maybe China now, or Hyperborea....

Welcome to the globalized world!
Haha, well it's good to see they actually exist! I ordered a few extras so may come in handy for a few projects.
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Old 13th March 2009, 03:45 PM   #10
emilvv is offline emilvv  Bulgaria
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Default finally package arrive

Hello,
After about 3 weeks caps came to me.
Very well packed ! ( thanks tedss.com ! )
If you use USPS service - please be patient !
Tracking over internet is not actual.

Emil
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