I would not apply 58 volts to old capacitors that are rated for 63 volts. I'd try to find a couple of caps rated at 75 or 100 volts.
If you decide to try these 63 volt caps, reform them thru high-value resistors (47k) before you attempt to apply full voltage without the current limiting resistors.
If you decide to try these 63 volt caps, reform them thru high-value resistors (47k) before you attempt to apply full voltage without the current limiting resistors.
Wagener said:
There is no firm rule on this. Anything over 10 years is suspect, 20 years highly suspect (assuming you can read the date code on the cap). Of course if they are leaking or dented, be very wary.
I've seen 30 year old electrolytic caps that worked just fine, and fairly new ones that failed. I tend to look at the manufacturer and the quality of the cap. Computer grade and high temp (105C) caps tend to last forever, while consumer caps from cheap makers fail withing a few years.
Phillips is a good brand. If the caps seem to have low leakage on a DVM ("resistance" slowly rising to infinite), reform them by supplying a trickle of current to them overnight, as the previous poster suggested. They will probably be fine if they are not extremely old.
If a used cap cost already half of what one retails new, I wouldn`t bother to buy used ones - especially when You don`t know how old they are!
I usually don`t buy even "new" surplus caps for much more than 10% of the normal retail price.
I don`t buy anything much older than 5 years.
I assume this is for an unregulated power supply.
If so, IMO caps rated for 63V are very marginal for unregulated +/-58VDC power supply.
Taken into account that there may be line supply voltage fluctuations, I`d consider about a minimun of +20% of the intended DC-supply voltage as safety margin for those caps.
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