capacitors

I don't know any other group to ask, but I presume people here
use capacitors.

Has anyone else notice that electrolytic capacitors don't
last as long as they used to?

I have some electronics from 20 or 30 years, or even older,
that still works fine.

Some things from two or three years ago with dead electrolytics.
If the can expands, it is easy to find which one, but they don't
always do that.

-- glen

On 6/5/2014 2:48 PM, glen herrmannsfeldt wrote:
> I don't know any other group to ask, but I presume people here
> use capacitors.
>
> Has anyone else notice that electrolytic capacitors don't
> last as long as they used to?
>
> I have some electronics from 20 or 30 years, or even older,
> that still works fine.
>
> Some things from two or three years ago with dead electrolytics.
> If the can expands, it is easy to find which one, but they don't
> always do that.
>
> -- glen
>

May be, it's a case of the "capacitor plague", a problem which emerged 
in 2000s?

http://en.wikipedia.org/wiki/Capacitor_plague

However, my hands on experience with capacitors is very limited.

Evgeny.

On 05.06.2014 12:48, glen herrmannsfeldt wrote:
> Has anyone else notice that electrolytic capacitors don't
> last as long as they used to?

Hm, not really.

> I have some electronics from 20 or 30 years, or even older,
> that still works fine.

It's a flawed comparison. Due to advances in technology, caps in todays
electronics have ripple currents that are vastly greater than your 30
year old pedants. Power supplies are almost uniformly SMPS constructions
(switched) where 30 years ago they rarely were. So it's not really a
fair comparison.

If anything at all, capacitors have become a lot better than they were
before. It is very possible to construct high quality electronics today.
The question is how you design (i.e. which value you choose and where
you place them on your PCB).

> Some things from two or three years ago with dead electrolytics.
> If the can expands, it is easy to find which one, but they don't
> always do that.

Most certainly all cheap consumer electronics.

Cheers,
Johannes

-- 
>> Wo hattest Du das Beben nochmal GENAU vorhergesagt?
> Zumindest nicht �ffentlich!
Ah, der neueste und bis heute genialste Streich unsere gro�en
Kosmologen: Die Geheim-Vorhersage.
 - Karl Kaos &#4294967295;ber R&#4294967295;diger Thomas in dsa <hidbv3$om2$1@speranza.aioe.org>

glen herrmannsfeldt <gah@ugcs.caltech.edu> writes:

> I don't know any other group to ask, but I presume people here
> use capacitors.
>
> Has anyone else notice that electrolytic capacitors don't
> last as long as they used to?
>
> I have some electronics from 20 or 30 years, or even older,
> that still works fine.
>
> Some things from two or three years ago with dead electrolytics.
> If the can expands, it is easy to find which one, but they don't
> always do that.

glen,

I have an aged NAD power amplifier, probably 20 years old, that has a
capacitor going bad in one channel. Haven't checked it out yet. But
yeah, I have experienced that.
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com

Randy Yates <yates@digitalsignallabs.com> wrote:

(snip, I wrote)
>> Has anyone else notice that electrolytic capacitors don't
>> last as long as they used to?

(snip)

> I have an aged NAD power amplifier, probably 20 years old, that has a
> capacitor going bad in one channel. Haven't checked it out yet. But
> yeah, I have experienced that.

My now 35 year old amplifier had two capacitors in the power-on
delay circuit replaced some years ago, and some years apart.
That was easy to figure out, as the relay took longer and longer
to close, until it didn't.

Some of the switches, such as the subsonic and high-cut filters,
have gotten noisy over the years. Time to bypass them, as I never
use them.

(I bought the service manual when it was new, just in case.)

But then one channel started to get some hum. To delay the need
to fix it, I bought a used one from a goodwill store. 

The latest is a HomePlug power-line network device. (Which came
from the goodwill store.) That one the capacitor top had expanded
so I knew which one it was.

I have a Sony DVD recorder that has some power supply problem,
probably a capacitor but I didn't find it yet. I bought a used
one of similar model (so the same remote works) but might still
fix that one.

But the worst one is digital TV converters, which last about 2 
or 3 years, each. One had an expanded capacitor so was easy.
Two more I still haven't fixed yet, but since one works, I am not
in so much of a hurry. 

Oh well.

-- glen

On Thursday, June 5, 2014 10:48:14 PM UTC+12, glen herrmannsfeldt wrote:
> I don't know any other group to ask, but I presume people here
> 
> use capacitors.
> 
> 
> 
> Has anyone else notice that electrolytic capacitors don't
> 
> last as long as they used to?
> 
> 
> 
> I have some electronics from 20 or 30 years, or even older,
> 
> that still works fine.
> 
> 
> 
> Some things from two or three years ago with dead electrolytics.
> 
> If the can expands, it is easy to find which one, but they don't
> 
> always do that.
> 
> 
> 
> -- glen

Most of us just use a line of code to replace capacitors

In today's devices caps seem to be the components that fail
first, especially in the low-voltage side of switched mode
power supplies which run in standby for long.

Have seen quite a lot of DVD-players, set-top-boxes etc with
blown-up caps.

Andre


On 05.06.2014 12:48, glen herrmannsfeldt wrote:
> I don't know any other group to ask, but I presume people here
> use capacitors.
> 
> Has anyone else notice that electrolytic capacitors don't
> last as long as they used to?
> 
> I have some electronics from 20 or 30 years, or even older,
> that still works fine.
> 
> Some things from two or three years ago with dead electrolytics.
> If the can expands, it is easy to find which one, but they don't
> always do that.
> 
> -- glen
> 

On Thu, 5 Jun 2014 19:21:50 +0000 (UTC), glen herrmannsfeldt
<gah@ugcs.caltech.edu> wrote:

>Randy Yates <yates@digitalsignallabs.com> wrote:
>
>(snip, I wrote)
>>> Has anyone else notice that electrolytic capacitors don't
>>> last as long as they used to?
>
>(snip)
>
>> I have an aged NAD power amplifier, probably 20 years old, that has a
>> capacitor going bad in one channel. Haven't checked it out yet. But
>> yeah, I have experienced that.
>
>My now 35 year old amplifier had two capacitors in the power-on
>delay circuit replaced some years ago, and some years apart.
>That was easy to figure out, as the relay took longer and longer
>to close, until it didn't.
>
>Some of the switches, such as the subsonic and high-cut filters,
>have gotten noisy over the years. Time to bypass them, as I never
>use them.
>
>(I bought the service manual when it was new, just in case.)
>
>But then one channel started to get some hum. To delay the need
>to fix it, I bought a used one from a goodwill store. 
>
>The latest is a HomePlug power-line network device. (Which came
>from the goodwill store.) That one the capacitor top had expanded
>so I knew which one it was.
>
>I have a Sony DVD recorder that has some power supply problem,
>probably a capacitor but I didn't find it yet. I bought a used
>one of similar model (so the same remote works) but might still
>fix that one.
>
>But the worst one is digital TV converters, which last about 2 
>or 3 years, each. One had an expanded capacitor so was easy.
>Two more I still haven't fixed yet, but since one works, I am not
>in so much of a hurry. 

I also have encountered a DTV converter with bad capacitors.
When I Googled, it turned out that model was notorious for a
particular cap going bad, probably a design under-spec.
(This was a cheapie unit.)

Best regards,


Bob Masta
 
              DAQARTA  v7.50
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              www.daqarta.com
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On Thursday, June 5, 2014 5:48:14 AM UTC-5, glen herrmannsfeldt wrote:

....

>  don't last as long as they used to?

Most of us don't, either!  :-)

(I can't believe I wrote that)

dvsarwate <dvsarwate@yahoo.com> writes:

> On Thursday, June 5, 2014 5:48:14 AM UTC-5, glen herrmannsfeldt wrote:
>
> ....
>
>>  don't last as long as they used to?
>
> Most of us don't, either!  :-)

That's what she said...
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com