RIFA replacement advice

[blindowl]

I want to replace the RIFA capacitors in a Macintosh IIci power supply but I’m having troubles finding components with the exact specs from my local electronics dealer.

• Is it okay to use caps rated for 275 V instead of 250 V? I know it’s normally okay to use capacitors rated for higher voltages, but as this is mains voltage I just want to make sure that the same applies to these?
• I can't find any 3300 pF Y (C6) film capacitor. Is it okay to use a ceramic filter capacitor with the same values instead? Specs here: https://www.electrokit.com/uploads/productfile/41010/otHV-Ceramic-Cap_dat_e.pdf

RIFA capacitors on this specific PSU (Astec AA15830):

C2: 0,1 uF X2 250V
CA: 0,047 uF X2 250V
C4: 4700 pF Y 250V
C5: 4700 pF Y 250V
C6: 3300 pF Y 250V

 

[cruff]

Yes it is okay to use a higher voltage rating replacement.

If the replacement for the Y type caps are also Y type caps then you can use a different type. If the ceramic capacitor is not Y rated then you can not use it as a replacement. Since you didn't specify the manufacturer's capacitor series in the PDF you linked I can't say for sure if this is the case or not.

 

[blindowl]

Thanks for your help! The ceramic cap is this one: https://www.electrokit.com/produkt/x1-y1-3-3nf-250v-10mm/

It says “X1/Y1”, so should be alright then?

 

[cruff]

Yes, that appears suitable. Here is a link to a good description of what the X and Y capacitor classes mean. https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/

 

[blindowl]

Yes, that appears suitable. Here is a link to a good description of what the X and Y capacitor classes mean. https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/

Thanks!