Using vintage capacitors in restorations

[tritone]

Originally Posted by G6Tanuki

Eeeek!!

I would suspect that the aluminium foils around the screw-penetration had been burned away by the HT arcing, sufficiently that normal operation could continue relatively-unaffected.

Yea G6Tanuki, it had to be something like that as there normally should have been a right 'ole mess inside if it had of expolded as you say. It still tests good on the meters. Lady luck weighed in I'd say on this occasion instead of Murphy.

(excuse me for side traking the thread a little bit folks)

[knobtwiddler]

Someone I work with inherited a Trinitron monitor from the video production firm across from our unit a couple of years back. We were speaking today and he told me that he'd re-capped the electrolytics, which had been a time consuming experience. I said to him 'I bet they all tested within tolerance after removal', to which he replied 'yep'.

[Tim]

Most of my polyester caps date from the 70’s& 80’s. Mostly cylindrical but a good number of those little yellow rectangular Philips types. All those I have used so far have been fine.

[GMB]

Look an a good data sheet and you'll see statements of average life expectancy at given temperatures.

Careful here. The "life" they are talking about is the time most will stay within its exact specification. The “useful life” can be many times longer.

The originals measure better than the new replacements as far as ESR is concerned.

Yes, I have run into this annoying problem too. It can be very disappointing that it is hard to find a modern part that is actually as good as the aged original. This is why I do not change parts unless they are definitely failing.

[whiskas]

Originally Posted by knobtwiddler

Someone I work with inherited a Trinitron monitor from the video production firm across from our unit a couple of years back. We were speaking today and he told me that he'd re-capped the electrolytics, which had been a time consuming experience. I said to him 'I bet they all tested within tolerance after removal', to which he replied 'yep'.

Nobody makes electrolytics as well as the Japanese.
I have tested 40 year old caps, well used and they still measure fine in most cases.
In my experience, it's pretty rare for a serious failure unless they are subject to excess heat (ie near a heatsink that runs a bit warm) or some other part has malfunctioned to put the capacitor under enormous stress causing it to fail through no fault of its own.