EEVblog #1183 - RIFA Madness (Schaffner Repair)

[Per Hansson]

The Schaffner FN 365-4/01 IEC line filter is a prime suspect too, it also contains Rifa caps and is documented to fail.
Infact the comment used as overlay in this video does refer to the Schaffner IEC filter.
Might be worth a quick teardown for the second channel?

[floobydust]

...
The newer RIFA caps should be OK - though it's odd to still find the same old series.

We have no idea if newer parts with the same part number have been miraculously "fixed". If Rifa/Vishay admit (fix) a problem, then it's a recall and lawsuits so I expect them to stay dead quiet.

The failure mode - paper dielectric with clear epoxy case, the metallization, moisture ingress etc. is not known. Every one I encounter has a cracked case, some have black spots inside.

[factory]

They definitely go off like firecrackers, but with a random time delay, has no one else managed to capture the magic smoke release on camera? I made sure to test these PSU's outside, I stopped after the third one smoked during an hour long load test, I saved the rest of the RIFA's I removed from the other PSU modules for November the 5th.

David

[xrunner]

Here's some I took out of an hp 3478A. 

The cracks remind me of nice old distressed furniture LOL.

[bitseeker]

Except for the spontaneous combustion part.

[Mortymore]

Happened the same to my Tek2445.
The smoke and the smell... ahhhh! Awful! 

[amyk]

has no one else managed to capture the magic smoke release on camera?

There's this memorable one, which happened at an amusingly appropriate time:

[artag]

Isn't a feature of X and Y caps supposed to be that they fail open-circuit ?
So you should be fine to plug it back in once they've gone bang

[thm_w]

Any ideas about the effectiveness of C1 and C2? They are in series with 22kOhm so even if they did go directly to earth ground, they wouldn't have much snubbing effect I would think.
Then they have drawn L1/L2 in series with these, so it makes it less clear where they are actually going.

[floobydust]

Those are green neon indicator lamps for L1 and L2 to PE, not for any EMI or snubbing use. C1 and C2 could not cause drama.

[thm_w]

Those are green neon indicator lamps for L1 and L2 to PE, not for any EMI or snubbing use. C1 and C2 could not cause drama.

Thanks, L1 and L2 meant lamp 1 and lamp 2, was confused with the L1.

[Yansi]

To add a bit of oil to the fire here, today I was servicing some piece of shit Metex power supply-multimetr-generator-counter combo and guess who was lurking behind the panel near the input socket? 

...

a nicely cracked RIFA piece of shit! 

[NiHaoMike]

There's this memorable one, which happened at an amusingly appropriate time:

Here's another BBC Micro where the X2 cap apparently failed leaky and "cooked" for a bit rather than hard short with an arc flash.