EEVblog #1183 - RIFA Madness (Schaffner Repair)

[EEVblog]

Repairing the Schaffner NSD200E Mains Interference Simulator.
And the dangers of bad mains filters capacitors, and RIFA brand in particular.

[Wolfgang]

It should be forbidden to design these parts into any equipment without a valid blasting and explosives handling license

[bitseeker]

Good ol' RIFA. We know them well.

The Schaffner Simulator, of course, has a Schaffner filter on the IEC connector, which is also famous for going bang. It needs replacing, too.

[sean0118]

Dave, you should test the cracked ones to destruction. Maybe outside?   

[floobydust]

These capacitors are still for sale, today. Vishay offers them, look at PME 271 series.
I'd emailed Vishay and said WTF are you doing still selling these? No response. The epoxy seems to shrink with age.

[wraper]

Good ol' RIFA. We know them well.

The Schaffner Simulator, of course, has a Schaffner filter on the IEC connector, which is also famous for going bang. It needs replacing, too.

Because they have those Rifa caps inside as well.

[Andy Watson]

Another victim of the Rifa virus!  Its starting to look like ordeal by Rifa caps is a rite-of-passge for anybody tempted by older equipment.

[bitseeker]

Good ol' RIFA. We know them well.

The Schaffner Simulator, of course, has a Schaffner filter on the IEC connector, which is also famous for going bang. It needs replacing, too.

Because they have those Rifa caps inside as well.

Yep, some of those filter modules even have a circuit diagram stuck on that shows that those caps are inside.

[johnlsenchak]

Rifa  madness  great   title  ! The question is , does  Dave have the munchies ?


It would be awesome if you connected that  test  device into a flat  screen  television or some other sensitive  electronic  device you found in the  dumpster room.  You can  see how those A/C  pulses  effect  the electronic  equipment under  test  conditions 

I use Surgex   surge  protectors  to protect  all my computer  equipment. The manufacture  states that  devices  under  load  can withstand  6KV  pulses using  Surgex  and have  proven that  fact in many   videos destroying  M.O.V.'s .  The  testing equipment  used to test Surgex  products  probably is very  similar to  the pulsing  device in this video.

I  do  believe  that Surgex  products  have  X/Y  filter capacitors on the main board , since  as  Dave would say " I take them  apart"

https://www.ametekesp.com/surgex

ESP Surge Demonstration
https://youtu.be/g0VFziFCM1c

[xrunner]

Reefer RIFA MAdness ! The TEA group knows all about it. 

He's holding one that just blew up -

[bitseeker]

 

[joeqsmith]

Nice job with the repair.  Hope to see a part III with it in action.   2.5KV at 10ns and it looked like a 50 ohm source, will the 121GW survive??

[Bicurico]

I am in process of repairing two PSUs from HP 8594E.

They contain 3 RIFA caps which I want to replace.

Can someone please guide me on how to find correct replacements?

Thanks,
Vitor

[Towger]

Hi Dave,

Did you get this one in the other module:



Don't forget the mains input filter, it will need to be replaced as well.

[EEVblog]

Hi Dave,

Did you get this one in the other module:

Damn, completely missed that, thanks.

[madires]

It should be forbidden to design these parts into any equipment without a valid blasting and explosives handling license

After the "big bang" Schaffner went for a different cap manufacturer for their line filters. Apparently it was a case of unplanned obsolescence. Also beware of NOS Schaffner line filters from that era. They provide an instant bang for the buck quite often.

[Yansi]

You know what is funny (or in fact is not)?

That the bloody ELEKTRO AUTOMATIK GMBH still uses these piece of shit capacitors in their premium priced power supplies.

[HighVoltage]

I had a fire in the lab once because of these RIFA capacitors an a Philips counter.
Luckily I was in the lab and could extinguish it.

Since then I always open up old equipment and exchange the parts.

[Kleinstein]

The RIFA caps are not the only ones to fail. Back in the 1970's there where several similar caps going bad. I faintly remember that there was a recall of TV sets because of faulty caps, that did not deserve the  X rating, as they sometimes failed with fire (not just smoke).

One still sees X-class caps used across the line in something like power tools fail - quite often when the motor turns bad an produces more spikes, but also without an obvious reason. Too much humidity seems to be not the only failure mode.

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

[Zbig]

Gee, must have sucked to be a RIFA employee. 10 out of 10, that's something... I feel for them. Just imagine this:

A grandson, wants to become an EE: "Grandpa, what did you do when you were younger?"
Grandpa: "I was working for R... I was a pimp."

Now I'll see myself out.

[tchicago]

Dave, the sine wave on the scope looks significantly distorted. Is this normal for the mains voltage?

[bsfeechannel]

I don't get the RIFA madness reference. Can some good soul explain it?

[Zbig]

I don't get the RIFA madness reference. Can some good soul explain it?

Come on, admit it, you haven't even tried: https://en.wikipedia.org/wiki/Reefer_Madness

[joeqsmith]

I don't get the RIFA madness reference. Can some good soul explain it?

Come on, admit it, you haven't even tried: https://en.wikipedia.org/wiki/Reefer_Madness

Or you can watch the whole movie on YT.   
https://youtu.be/zhQlcMHhF3w

[Towger]

I don't get the RIFA madness reference. Can some good soul explain it?

100% failure rate.  I send Dave some New Old Stock RIFA suppression caps I had in a parts draw for EEVsmoke, about a year back.

[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.