68kMLA Classic Interface

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RIFA cap replacement for Mac Classic analog board
Posted by: Bagpuss on 2026-02-19 02:36:50
I've had a look around but I haven't been able to find a conclusive answer. I have a couple of Mac Classic analog boards, one of the older version (820-0395) and one of the newer (820-0525). They both contain a set of two RIFA PME 290 MB caps, and on the newer board they are cracking at the top. I am about to recap this board and I might as well get some replacements for the RIFAs.

There appears to be a direct replacement from RIFA, the PME 271 Y, but this is difficult/expensive for me to get hold of (I am in the Netherlands). I came across B32021A3103M from EPCOS/TDK, which is a 10nF 300V Y2 (image attached is of a box I found on the internet, I haven't ordered 100 of them!) I don't know a lot about safety capacitors but I am assuming that it being rated at a higher voltage wouldn't matter? Also unfortunately these caps are 10mm spaced and not 15mm like the current caps, but I could just bend the leads to make them fit.

Alternatively do you know of another part that I could use?

Thanks!
Posted by: Nixontheknight on 2026-02-19 06:14:17
Replace the X caps with X2 rated ones, and the Y caps with Y2 rated ones
Posted by: bibilit on 2026-02-19 06:40:07
Caps are most of the time cracked on the Classic AB, neved have the issue present on other models, i leave them alone...
Posted by: nyef on 2026-02-19 15:04:14
There's a line of argument that I've heard a time or two that RIFA caps are entirely to prevent noise from moving from the hardware into the building power lines, and are therefore entirely optional. That is, you can remove them without replacement and not have any problems. I don't know how much credence I give to this argument.

Also, if a RIFA cap lets go, it's obnoxiously odorous, and the mechanism for them letting go is moisture getting in through the cracked casing.
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