I thought it was a myth...

[forr]

perhaps your 25 years old ELNA's have lost most of their capacitance over the years.

A myth is that aging electrolytics loose their capacitance. Having a cap-meter and a tan-delta-meter, I have tested more than two thousands of them. I'do not remember some having significative capacitance loss. More often it is that the ESR which has increased, but less often than may be thought.

[AC439]

Thanks again for more ideas. I'm working a couple of night shifts in a row and will be off Wed. I will take some pics, do some measurements and post result. I hope I can find a way to measure ESR as well. I do not have a scope nor a capacitance meter, only regular bench tools such as a voltage adjustable regulated power supply and a couple of multimeters.

[Jim W]

Originally Posted by forr

A myth is that aging electrolytics loose their capacitance. Having a cap-meter and a tan-delta-meter, I have tested more than two thousands of them. I'do not remember some having significative capacitance loss. More often it is that the ESR which has increased, but less often than may be thought.

I pulled and measured six big Elna (IIRC) PS caps out of a late 70's HK power amp and they all came out 15-20% short of nominal. The replacement Panasonic TSs all tested over their rated values. I can't say that the Elnas weren't below spec when they went in, but it seems unlikely. A sample of six isn't particularly statistically worthwhile compared to a couple of thousand, but my experience was pretty consistent and contrary to yours.
Regards,
Jim W.

[forr]

Hi Jim W

15-20% short of nominal value of capacitance is not very significative for electrolytics.Below a link to a catalog of a french manufacturer which provides useful information about their life.

http://www.microspire.com/fichiers/c...safco_2010.pdf

I do not remember having seen a faulty cap from this manufacturer, even old, their specs are usually impeccable or, at least, never need replacement.
Some years ago, I built Cyril Bateman's tan-delta-meter. As no more than one of my caps stock seems to be faulty when tested, Cyril sent me some samples of really faulty caps to proove that they exist and that the device he conceived works well.
I primarily built this tan-delta-meter to check electrolytics of professional electronic flashes for photographers which delivers huge amounts of current in a few ms. They were more than 30 years old and have been used a lot. Having all a tan-delta inferior to 0.01, none had to be rejected.

[AC439]

Hi eveybody.....I managed to take some pics today (after 3x12 hrs night shifts). As you can see the 4700uF is non-brand, and very small size (pics taken with a US quater by its size). You can also see its size in compare to my great sounding antique ELNA 6800uF cap. There is another pic that compare it to an old 2200uF Rubycon.

I haven't been able to find simple way to measuring ESR. The information I found involves equipments I don't have - sig gen and an OSC scope.

But then again, I went to digikey and mouser and can't find newer ELNAs that are comparable to the size I'm using. Biggest one is about 3300uF. ARe these all they are making now ? Nothing bigger than 3300uF ?

I also search for Panasonic FM in digikey and mouser and they don't have it. They are listing different Panasonic series that are not FM. I'm kind of lost but I want to avoid buying caps from Ebay if by all means possible. Where do you guys buy your filtering caps from ?

This is my thread of the JLH I built:
My JLH 1996 EVO....output transistors questions....


regards,
-AC

[mctavish]

The printing on those Panasonic caps looks a bit suspect to me....

[AC439]

Originally Posted by mctavish

The printing on those Panasonic caps looks a bit suspect to me....

I don't have any panasonic caps in my pictures. Are you sure you are seeing panasonic ?

[Andrew Eckhardt]

Matsushita (the reason for all the "M"'s printed on the plastic, owns panasonic. By the way those look fine to me,

[sek]

Originally Posted by AC439

I don't have any panasonic caps in my pictures. Are you sure you are seeing panasonic ?

The (M) logo is that of Matsushita, also known as Panasonic.

Your pictures presumably show a TS-HA series cap. According to the datasheet, the 35V/4700uF type should be of around 25mm diameter and height.

Additionally, the 0488 marking looks like a production code of week 4 in 1988.

[Andrew Eckhardt]

Digi-Key - P6600-ND (Manufacturer - ECO-S1VA472CA)