Confusion about replacement AC film caps

[Surfheart]

Hi again

I have a mac plus that trips my house power soon after it's booted.

From another thread I found that the likely culprits are the two small capacitors mounted vertically close to the power switch.

I desoldered them last night and noticed that they are cracked.

The markings on them are 4700pF 250V Y class.

I'm in Australia and there is a local component shop called Jaycar that carry this sort of stuff but I can only find X2 class caps.

Like these :  250V AC Mains - Metallised Polypropylene Capacitors - X2 10nF

Their full range of these types of capacitors is here

There are others there  with an N designation for which I have no idea what that means, e.g. 22N, 47N

I've read elsewhere that it's not good to replace Y class with X class and I don't want to blow anything up or start fires

Any advice would be greatly appreciated.

 

[techknight]

Type X is Across the line, meaning between Neutral and Hot. 

Type Y can only be used across Neutral, or Hot to Ground. 

You cannot interchange these. 

You also cannot interchange Y1/Y2, and X1/X2 they are rated differently. 

 

[Surfheart]

Type X is Across the line, meaning between Neutral and Hot. 

Type Y can only be used across Neutral, or Hot to Ground. 

You cannot interchange these. 

You also cannot interchange Y1/Y2, and X1/X2 they are rated differently. 

Thanks Technight, So I assume I can't use the caps that I linked too.

The reason for my confusion is that in this other thread it was recommended to replace these caps with 10nF (0.01uF) Met Poly Class X2   X210N

 

[techknight]

Yea you cant replace Y rated caps with X, or X2. 

You must use Y for Y, and X for X, Although I dont know if they make a universal or not. 

Have a look here for further detailed information :http://www.justradios.com/safetytips.html

This site is based around tube stuff, but the concepts are still identical. 

The purpose of these caps are to form a pi filter to prevent common mode noise from getting back into the line. 

 

[Surfheart]

Thanks again technight,

Would either of these be suitable? or would one be more suitable than the other?

http://au.element14.com/epcos/b81123c1472m/cap-film-pp-4-7nf-250v-rad/dp/9751513

http://au.element14.com/kemet/pme271y447m/cap-film-paper-4-7nf-1kv-rad/dp/9717552?ost=9717552

Thanks again!

 

[Surfheart]

I noticed that there is a larger filter cap. It looks ok but would it be worth also replacing this in an effort to solve my circuit breaking Mac plus issues?