Replacement for vintage Sprague axial capacitor

[chris48]

Hi, I need some help. I have done some research but still can't find enough information about this Sprague 25uF 0-25VDC axial capacitor.

It looks like it needs to be replaced. Any suggestion is most welcome.

🙂🙂🙂

 

[NareshBrd]

What happened that it needs replacement?
Put a 25 uF/35V, maybe need a longer lead if you get radial only...

 

[chris48]

Its in an amplifier I bought 30 years ago. I suspect the cap is even older. It looks like the red cap/seal is breaking or melting and since I already have it opened up, I just might do some work to make it last longer. It is running alright.

 

[NareshBrd]

If you can, check for leakage with resistance range in 10k or so with a meter.
Also, if you have one, check its capacitance with a meter.

Could be age related break down of the casing.
Sprague are good, I don't know what kind of capacitor this is.

You looked for a replacement in axial construction?
What is its function in the circuit?

 

[chris48]

Thank you Naresh. This is in a power supply board. Not sure what's its function though. I have a regular meter and can check the capacitance but don't have a ESR meter. I know Sprague is good so I want to get a good replacement. For peace of mind.

 

[rayma]

An example, but make sure the part that you choose is not too long for the space.
It is not worth testing that old capacitor, just replace it.
https://www.newark.com/vishay/mal20...-GEN-Shopping-NewStructure-Passive-Components

 

[chris48]

Thank you for the suggestion. I checked and I will go with the 105 degree version. No problem with space. The length allowance is 25mm.

 

[Mark Tillotson]

This is the only +/-10% 25uF cap I could find at Farnell:

https://uk.farnell.com/multicomp-pro/mcax25v256k6x13/aluminum-electrolytic-capacitor/dp/1600775


That sort of tolerance for an electrolytic is rare.

 

[rayma]

Thank you for the suggestion. I checked and I will go with the 105 degree version.
No problem with space. The length allowance is 25mm.

Up the voltage and uF a bit if there is room. It's just a regulator bypass.

 

[mdpaudio]

I would use a 47uf 35 volt 105C axial cap. Brand is not critical in this position as no audio goes through it.

 

[chris48]

Thank you for all the suggestions. I initially just wanted to restore the amp in an authentic way. Vishay is still producing the Sprague axial caps, but their price and specs are kind of disappointing. Illinois also has some axial caps. Priced even higher.

Would the Sprague (bigger size) last longer than the radial caps?

 

[mdpaudio]

Axial and radial last the same. The 105C helps a lot and so does using a higher voltage cap so there is less stress on it.

 

[wiseoldtech]

I would use a 47uf 35 volt 105C axial cap. Brand is not critical in this position as no audio goes through it.

Or, a 47U 50V cap.
A radial even works there.

 

[NareshBrd]

If 50V are not available, put a 63V instead.

 

[chris48]

The amplifier has served me well for the past 30 years. Good enough for me. Very much hope it would outlast me.😀😀😀

 

[chris48]

Just curious. Anyone know when the cap was made? In the 90's?

 

[NareshBrd]

What is the amp make?
Track side soldered components with through holes...late 80s or up to 1995 or so.
No heat sink for the power transistor.
It has worked well, and in most cases would be considered end of life.
If it is still working well, a nice well designed and well made unit, with generous component ratings.
Treasure it.

 

[chris48]

It is the power supply unit to a Cello preamp made in the early 90's. The enclosure is completed closed. The cap is the only component showing any signs.