More about RIFA capacitors kzread.info/dash/bejne/inWW1LdqZ8uyhLA.html kzread.info/dash/bejne/m5-kl6SooqzVj7A.html

I also had a Rifa embedded in a line filter socket blow up - in a Tektronix signal generator from the mid 90's.

This happened to me about 4 months ago. I was working on getting ProDOS installed on my SCSI2SD connected to my Apple //e. I took a break for some lunch, and left the machine idle. When I came back (maybe 2 hours later), whew! My office smelled AWFUL. lol. I never got to see the magic smoke, but I knew right away what it was. I opted to replace the RIFA cap in the power supply for my Apple, but it was working fine with the bad cap. It just really reeked. 🙂 Like always, great video Hutch!

A new 8050 mini that used 3.5" disks would be awesome.

Oh geez, thanks Chuck. I had no idea there were Rifa's in the pets like that. I'm good about swapping them out of everything but i would have never noticed this or looked in the power socket. Thanks for posting.

Nicely done! I should probably do this on my PET 2001 and PET 4032 machines.

@HutchCA

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It's doubtful your 2001 has one. Generally if it has an attached power cord, it doesn't have any mains filtering caps. At least not in North America, but European units can have one installed under the transformer. Commodore didn't worry about FCC requirements until around 1981 which is when they started using C14 power sockets instead of fixed power cords.

@geekwithsocialskills

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@@HutchCA Now that I look, you're correct, my 2001 does have the power chord attached, however the 4032 that I'm currently restoring has the same plug setup as your SuperPET.

@RudysRetroIntel

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Thanks for sharing. I've replaced the rifa caps on my Apple II power supply however, I didn't think to check my PET 4032. Guess I better get on it asap.

Magic smoke from RIFA™, thanks for your video. I do copy the connection way from one from a broken DELL power supply, it's easy to scavenge the capacitor from PC power supply or some of the home appliance IEC socket, save some bucks buying from Mouser or Farnell, just two 470pf Y2 grade capacitor from Earth to Live and Neutral.

You can always solder in an x2 cap across the terminals on the iec socket.

@HutchCA

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Sure, but if I were to do something like that, I'd want to do it past the power switch so it's not energized all the time. Also the filters in these C14 sockets also contain inductors and Y type capacitors in addition to the X type. It just doesn't seem worth the effort to me.

@jamesbennettmusic

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@@HutchCA perhaps there's room to do it on the transformer primary tags?

@HutchCA

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@@jamesbennettmusic I'm sure it could be easily done, I just don't think it's worth the trouble no matter how easy it is. YMMV if you still listen to AM radio around the house.

@jamesbennettmusic

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@@HutchCA I guess the reality is it was probably only really done to swing the FCC approval in their favour, and for all the capacitors you could replace it with, we now live in a world utterly full of noisy consumer power supplies that weren't around back then. So in the grand scheme it's not so critical.

@ChartreuseKitsune

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@@HutchCA Inside the original filter the inductor is likely a common mode choke right before the filters. Then it's two smaller class Y caps from L to Earth and Neutral to Earth (Something like 0.01uF), then a class X from live to neutral (Typically 0.1uF or so). Even with the choke removed they still do provide some EMI benefit just on their own (of course it won't harm the device to leave them out, but may introduce some radio noise.

Does remind me that I should double check my 2001N, though I think those are unfiltered entirely (the cord is hard wired, and I don't believe they bothered with a small board under the cover to mount the filters).

@HutchCA

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In Europe, on the older units, they did sometimes installed an RFI filter wired in under the transformer. Not sure what was in the can, maybe just a single X type, but I have seen photos of those having failed also. It's not clear if they were installed by Commodore or by European importers but I've never seen one in a North American unit. Commodore didn't start dealing with FCC certifications until '80 or '81 If I ever do replace the filter, I think it would be better to install it past the power switch so it's not energized 100% of the time.