Apple II Astec PSU repair, source of paper line filter caps?

[Byrd]

Hi,

I recently picked up a beige Apple IIe, which appeared to work but after 10 seconds the PSU started to give out a loud sizzling sound - the computer continued to work.

Open up the PSU case, and I believe the smell/culprit is two "paper line filter capacitors":

- 0,1 uF 250V looks the worst, very cracked and bulging metal sides

- 0.47 uF ? assume 250V ? looks intact, but best to replace

See here for a pic I found of the culprits:

http://www.classic-computers.org.nz/blog/2011-04-28-apple-iie-adventures1.htm

... where can I obtain replacements from? I'm unable to source them, my electronics knowledge is lacking here. As a sidenote, the capacitors look "OK" on the PSU.

Thanks

JB

 

[Byrd]

More research has revealed that I need some metalised polypropolene capacitors, and my local electronics store sell these:

http://www.jaycar.com.au/productResults.asp?MID=1&SSUBID=636&SUBCATID=967&keyform=CAT2#1

... what's the X2 moniker mean?

 

[CelGen]

When I redid my Lisa's PSU the shop recommended I replace them with polyester capacitors.

I have not had a problem using those.

 

[Byrd]

I love researching this sort of stuff, learning more about electronics. I purchased both polypropolene caps as mentioned, and the PSU works a treat. During this process I also replaced the 10V 220 uF capacitor near the heatsink that apparently is a common weak point, even though it looked fine. The old paper caps were cracked and split in several places, when they fail they reportedly give off a terrible smell that lingers for days - thankfully I didn't have the Apple II on for long to work out something was wrong.

 

[bear]

That is basically the solution. Use polyester, metallized poly, or mylar caps. They're all essentially the same, for this application.