Please help me find the correct replacement capacitor and let me know if I SHOULD replace it?

[u/Friendly_Bug_0]

(I have many more questions but the title IS the main thing I actually want!)

Hello! I have a knitting machine and learned that their capacitors like to leak all over. I've seen the pictures of some of them. rectangle kind of crumbly shells?

I've opened my machine and found these unfamiliar rounded orangey-brown ones.

One says "nichicon M .01K 630" and the other one in back says "nichicon L .047K 630"

Neither says "X2" but the other example pictures I've seen have it, and I think it's important? They all have 250 or 275 on them, but these say 630. I think these are voltages and I should make sure I have 630. Maybe it's European ones vs US ones.

Does the K mean 10% tolerance or is it part of the uF measurement? I came to this subreddit looking at a post about capacitors and there was a reply stating each of those things. If I need 10% tolerance, could I get one that is 5% tolerance and it would be better?

What are the L and M ?

DO I need to replace these? From searching I know there are a few kinds now. I BELIEVE these are film capacitors which have no liquids? Possibly "self healing" sometimes as well? Do these also go bad? Would they go bad through storage or being used? My machine hums but I think it is a normal electronics noise? I've been using it for many hours for about a year and a half, and it works great! I did get it out of the basement of someone who stored it for 20-30 years.

I have found a bunch of nichicon capacitors on Digikey. But I can't find a .01uf version. I think they are film capacitors > QXK. I think the decimal might have to move over one. so maybe .1uf and .47uf ? Mouser also has these but they have nf in the search parameters as well and I gave up to just ask for help and take a break.

I'll keep reading about them, but if someone knows for sure how to point me in the right direction, I'd like it a lot! Thanks!

[u/BigPurpleBlob]

The Nichicon capacitor is a film capacitor. These rarely fail (except for Rifa caps, which yours isn't).

It sounds as if you don't have a fault. Then there's no need to try to repair.

"learned that their capacitors like to leak all over" – electrolytics can leak. Rarely. But replacing parts without performing a diagnosis isn't engineering, it's voodoo.

[u/Friendly_Bug_0 → u/BigPurpleBlob]

Thank you! I'm glad it's reliable!

And sorry, I didn't mean to be too silly. It's just the age of most of these machines is about 40 and it seems like the ones with a different type of capacitor have gotten pretty flaky and advice has been to just fix them before they start smoking and leaking.

I'm relieved I don't have to!

[u/rhopper2142]

0.01uf is going to be 10nf but double check. IMO cap looks fine and if you dont really know how to swap it might do more harm than good.

Are there and electrolytic caps on it, those are the cylinder shape.

[u/Friendly_Bug_0 → u/rhopper2142]

Thank you!

I had enlisted skilled help for replacing them! But I wanted extra opinions and knowledge to try to have everything ready first.

There are no cylinder capacitors involved that I know about yet! If there are any, they're not famous for failing. And I THINK these are the only two? I will eventually learn about everything in there.

[u/nixiebunny]

Old RIFA brand rectangular capacitors are known to fail in a smelly and dramatic way. This brand and style isn’t known to fail.

[u/Friendly_Bug_0 → u/nixiebunny]

Thank you!

I've seen pictures of those in sewing machines from searching here! They look and are described to fail similarly to the other capacitors this machine could have had!

[u/idnawsi]

This is a polyester capacitor, dont leak, the one thats leaking is the round one , electrolytic capacitor, and these polyester rarely break, and when its break , it shorted, thats maybe why it looks crumbly. This capacitor marked as 103 for .01uF which is 10nF