concerns over recapping

[jbivy]

So ive begun recapping my 50 motorola table top tv (12t3 chassis). Had to go through several sites to find them all, apparently a few are odd.

Ive had to use two NOS black beauties, the age of them bothers me somewhat. Im worried that theyll immediately burn out, or quickly so, or just be bad from age. Or perhaps im just a perpetual worrier.

Then im using new caps for the common ones. Though theyre all normal(big) sized, one is tiny. A 10uf 50v, its just..tiny. Around the size of three pencil erasers stacked, its replacing what was a rather large cap (size of an A battery). I showed this to my uncle, whos always been into electronics, repaired tv's in the 60s and he says its fine. That the new ones simply are far better than the old girls, made of better materials.

Do I have anything to worry about?

Again, sorry for so many newby questions. The extent of my electrical prowess to date has just been recapping a few old radios, replacing wires, tubes and such. This is all new to me.

[bandersen]

The black beauties could cause you some problems, but your uncle is right - that tiny 10uF is fine. They really are that much smaller these days.

What's the value of those NOS caps ? I or someone else might have what you need.

[Findm-Keepm]

Originally Posted by jbivy

Again, sorry for so many newby questions. The extent of my electrical prowess to date has just been recapping a few old radios, replacing wires, tubes and such. This is all new to me.

DON'T EVER apologize for being a newbie! We all were newbies at some time....

If anything, you deserve credit and praise for restoring historical electronics!

What values are the black beauties? Some of us have extensive parts bins and can help out with oddities and the hard-to-find stuff. Feel free to ask in the forum - we all need a little help sometimes.

Cheers,

[bgadow]

I've tried NOS black beauties before and they blew up just as quick as the original ones! If you can't find the correct value, you can parallel two caps that add up to the capacitance you need. For example, if you needed a .012 cap, you could parallel a .01 and a .002. For the most part you don't need that much precision, though.

[Eric H]

What Bryan said, it usually doesn't have to be exact, .047 to replace a .05 for example, or a .022 in place of a .025, these are still within the 10%-20% spec that most of the original caps had.

The exception would be very small Pf value Micas and Ceramics but those aren't often replaced.

A higher voltage is always acceptable when replacing paper caps, I (and most everyone else) use the 630 volt caps for everything, they are all smaller than their ancient counterparts, even if they were only 200 volts originally.

What were the values you had to use Black Beauties for?
I haven't run into a cap in a TV yet that I couldn't find a new replacement for.

[jbivy]

Okay, i feel better knowing that i can parallel these and make an equivalent. That they can be off by a tiny percentage, it would make this a ton easier the next time..

The two I couldnt find and used NOS ones were a .005uf-1,600v and a .006uf-600v. Seems like i could have used a .005-600 for the latter one, guess ill be ordering another of those now.

Oh darn.. just re-looked on the web and found the .006-600.. Well that teaches me to be in a rush and order things quickly. Ive found several .005-1,600's but theyre either clear plastic coated aluminum ones being sold as NOS (No idea their vintage) or old NOS black beauties.

[bandersen]

You can get Sprague OrangeDrop caps rated at 1,600 from a number of vendors. 0.0047 is close enough to 0.005.

Antique Electronic Supply

Radiodaze

Mouser

[ctc17]

I cleaned out several old tv shops and their stock of caps. Every single one was bad. Leaky, lossy, off value etc.
I wouldnt dare use old caps. You are going to be chasing your tail. Even with the orange drops, new old stock is unacceptable. You want new recently manufactured caps.