exxos's Atari, Amiga & retro forum

I'm looking for replacement capacitors for my Apple IIe PSU, and the originals are as follows:

• 1uF Class X 250V - On the PCB, C1
• 47uF Class X 250V - Directly across the Kettle lead socket

They are both RIFAs and looking quite stressed and cracked. I do need to double check their part number, but for now I am assuming they are X1.

I'd like to replace them with non-RIFA types, so perhaps polyester, and I was wondering if X2 would be suitable? I understand the surge voltage for X1 is between 2.5KV & 4KV, and that the X2 is <=2.5KV, but since my knowledge is limited I wanted to pose the question to all of the clever people here who understand better than me about these ratings.

I am kind of considering that I could ditch the one directly across the mains altogether, but always best to ask advice first :)

You can replace them with (almost) any X class capacitor. The parametric searches on the Mouser or Digikey will allow you to match pin pitch too so they slot in nicely. I buy Kemet or other quality polyputthekettleon X class caps to replace the paper RIFA parts. They cost circa 50p.

cmorley wrote: 13 Aug 2021 13:51 You can replace them with (almost) any X class capacitor. The parametric searches on the Mouser or Digikey will allow you to match pin pitch too so they slot in nicely. I buy Kemet or other quality polyputthekettleon X class caps to replace the paper RIFA parts. They cost circa 50p.

Fantastic, thank you. As it goes, I just managed to get a view of the part numbers and sort of answered my own question, they are in fact X2s, but I really appreciate that as I now know for the future :)

Not sure why they couldn't have printed X2 on the case rather than just X.

The one on the mains socket is enormous, and I expect would have generated a large amount of smoke!!

I'll have a look at the Mouser/Digikey search to see if I can match them up, thanks again.

They're only mains filtering capacitors so it would work without them at all technically. The values aren't that important either, as long as they fit the holes, are the right voltage rating and in the same ball park capacitance.

X capacitors are supposed to fail with the leads non-shorted and Y capacitors fail with the wires shorted. X and X2 seem to be the same, with the X2 being newer and different for "reasons".

I just buy the polypropylene(?) ones from RS as a bag of 20 or so.

stephen_usher wrote: 13 Aug 2021 14:10 They're only mains filtering capacitors so it would work without them at all technically. The values aren't that important either, as long as they fit the holes, are the right voltage rating and in the same ball park capacitance.

X capacitors are supposed to fail with the leads non-shorted and Y capacitors fail with the wires shorted. X and X2 seem to be the same, with the X2 being newer and different for "reasons".

I just buy the polypropylene(?) ones from RS as a bag of 20 or so.

Reading about the X1/X2 differences it seems only the surge voltage that differs, and I read the same about them failing open circuit for safety, but appreciate all that stuff being solidified by those in the know :)

rubber_jonnie wrote: 13 Aug 2021 14:55 Reading about the X1/X2 differences it seems only the surge voltage that differs, and I read the same about them failing open circuit for safety, but appreciate all that stuff being solidified by those in the know :)

Yep. As they are across the mains side of things, they are X-rated for more hardcore action and abuse.

exxos wrote: 13 Aug 2021 15:04

rubber_jonnie wrote: 13 Aug 2021 14:55 Reading about the X1/X2 differences it seems only the surge voltage that differs, and I read the same about them failing open circuit for safety, but appreciate all that stuff being solidified by those in the know :)

Yep. As they are across the mains side of things, they are X-rated for more hardcore action and abuse.

:lol: :lol: :lol: