Is this class X capacitor any good?

[StarkRG]

I'm getting ready to replace all the electrolytic capacitors in my Mac 512ke (entirely precautionary given it's about 33 years old) and discovered that its class X capacitor has some visual issues, its plastic dip skin is cracked and falling apart. I don't have a lot of knowledge about power supplies so I don't know what kind of capacitor this is (other than clearly being a class X, both because it has X on it and because it's across the live and neutral). I'm guessing it's not an electrolytic capacitor, and the skin is probably crumbling because it's old rather than because the capacitor expanded, but I'm not confident enough to just ignore it.

Here are the pictures: https://imgur.com/a/ps2tGcj

If it does need to be replaced, can anyone give me an idea of what I should be looking for? (digikey doesn't have a "class x capacitor" section )

[mzzj]

I would be willing to guess that its a WIMA brand 
well known for cracking and/or catching on fire

Last column "ratings" has option for X2 filter
https://www.digikey.com/products/en/capacitors/film-capacitors/62?k=x2%20capacitor

[Gyro]

That's the infamous Rifa metalized paper cap, smoke and flame will soon erupt! 

Replace with an equivalent value X cap without delay - even better, before powering it up again.

[mzzj]

OK, what I was thinking?    Rifa is the more "famous" also around here.
(in my defense I have seen some wima brand paper caps also failing) 

[bd139]

Evict it quickly!

To give you an idea how often these explode, I actually came across my 7th exploded one two weeks ago:



Replace it with anything about the same capacitance, that is X2 rated and has the same pin pitch and same or better voltage rating.

Honestly the RIFAs are pretty good. They had a design life though. I tend to put new RIFAs (now sold by Kemet) in where old ones failed and stick a sticker on the back with "replace RIFAs after DATE" where DATE is 10 years in the future.

[Gyro]

Honestly the RIFAs are pretty good. They had a design life though.

Yes, they do have higher dV/dt ratings than MKP ones. If it wasn't for the cracking and moisture ingress they'd be really good. Who knows, the epoxy composition might be more resilient these days.

[bd139]

The new kemet ones are a different colour so possible. Fingers crossed! (and stuffed in ears  )