EEVblog #1183 - RIFA Madness (Schaffner Repair) - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: February 23, 2019, 11:48:44 pm
content: Repairing the Schaffner NSD200E Mains Interference Simulator.And the dangers of bad mains filters capacitors, and RIFA brand in particular.

author: Wolfgang
author_rank: Super Contributor
timestamp: February 24, 2019, 12:34:36 am
content: It should be forbidden to design these parts into any equipment without a valid blasting and explosives handling license

author: bitseeker
author_rank: Super Contributor
timestamp: February 24, 2019, 01:18:26 am
content: 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.

author: sean0118
author_rank: Frequent Contributor
timestamp: February 24, 2019, 01:30:40 am
content: Dave, you should test the cracked ones to destruction. Maybe outside?

author: floobydust
author_rank: Super Contributor
timestamp: February 24, 2019, 01:31:44 am
content: 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.

author: wraper
author_rank: Unknown
timestamp: February 24, 2019, 01:35:51 am
content: Quote from: bitseeker on February 24, 2019, 01:18:26 amBecause they have those Rifa caps inside as well.

author: Andy Watson
author_rank: Super Contributor
timestamp: February 24, 2019, 01:55:58 am
content: 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.

author: bitseeker
author_rank: Super Contributor
timestamp: February 24, 2019, 02:03:29 am
content: Quote from: wraper on February 24, 2019, 01:35:51 amYep, some of those filter modules even have a circuit diagram stuck on that shows that those caps are inside.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: February 24, 2019, 02:40:32 am
content: 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 conditionsI 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/surgexESP Surge Demonstrationhttps://youtu.be/g0VFziFCM1c

author: xrunner
author_rank: Super Contributor
timestamp: February 24, 2019, 02:47:02 am
content: ReeferRIFA MAdness ! The TEA group knows all about it.He's holding one that just blew up -

author: joeqsmith
author_rank: Super Contributor
timestamp: February 24, 2019, 05:04:54 am
content: 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??

author: Bicurico
author_rank: Super Contributor
timestamp: February 24, 2019, 09:27:18 am
content: 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

author: Towger
author_rank: Super Contributor
timestamp: February 24, 2019, 10:14:58 am
content: 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.

author: EEVblog
author_rank: Unknown
timestamp: February 24, 2019, 10:25:16 am
content: Quote from: Towger on February 24, 2019, 10:14:58 amDamn, completely missed that, thanks.

author: madires
author_rank: Super Contributor
timestamp: February 24, 2019, 11:49:24 am
content: Quote from: Wolfgang on February 24, 2019, 12:34:36 amAfter 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.

author: Yansi
author_rank: Super Contributor
timestamp: February 24, 2019, 12:11:17 pm
content: 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.

author: HighVoltage
author_rank: Super Contributor
timestamp: February 24, 2019, 01:01:50 pm
content: 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.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 24, 2019, 01:35:34 pm
content: 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.

author: Zbig
author_rank: Frequent Contributor
timestamp: February 24, 2019, 04:29:24 pm
content: 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.

author: tchicago
author_rank: Regular Contributor
timestamp: February 24, 2019, 05:10:59 pm
content: Dave, the sine wave on the scope looks significantly distorted. Is this normal for the mains voltage?

author: bsfeechannel
author_rank: Super Contributor
timestamp: February 24, 2019, 05:11:16 pm
content: I don't get the RIFA madness reference. Can some good soul explain it?

author: Zbig
author_rank: Frequent Contributor
timestamp: February 24, 2019, 05:17:30 pm
content: Quote from: bsfeechannel on February 24, 2019, 05:11:16 pmCome on, admit it, you haven't even tried:https://en.wikipedia.org/wiki/Reefer_Madness

author: joeqsmith
author_rank: Super Contributor
timestamp: February 24, 2019, 05:20:06 pm
content: Quote from: Zbig on February 24, 2019, 05:17:30 pmOr you can watch the whole movie on YT.https://youtu.be/zhQlcMHhF3w

author: Towger
author_rank: Super Contributor
timestamp: February 24, 2019, 05:48:19 pm
content: Quote from: bsfeechannel on February 24, 2019, 05:11:16 pm100% failure rate. I send Dave some New Old Stock RIFA suppression caps I had in a parts draw for EEVsmoke, about a year back.

author: Per Hansson
author_rank: Unknown
timestamp: February 24, 2019, 07:52:34 pm
content: 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?

author: floobydust
author_rank: Super Contributor
timestamp: February 24, 2019, 08:44:47 pm
content: Quote from: Kleinstein on February 24, 2019, 01:35:34 pmWe 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.

author: factory
author_rank: Super Contributor
timestamp: February 24, 2019, 10:04:40 pm
content: 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

author: xrunner
author_rank: Super Contributor
timestamp: February 24, 2019, 10:59:59 pm
content: Here's some I took out of an hp 3478A.The cracks remind me of nice old distressed furniture LOL.

author: bitseeker
author_rank: Super Contributor
timestamp: February 25, 2019, 12:09:13 am
content: Except for the spontaneous combustion part.

author: Mortymore
author_rank: Frequent Contributor
timestamp: February 25, 2019, 12:44:13 am
content: Happened the same to my Tek2445.The smoke and the smell... ahhhh! Awful!

author: amyk
author_rank: Super Contributor
timestamp: February 25, 2019, 03:04:06 am
content: Quote from: factory on February 24, 2019, 10:04:40 pmThere's this memorable one, which happened at an amusingly appropriate time:

author: artag
author_rank: Super Contributor
timestamp: February 25, 2019, 09:20:10 pm
content: 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

author: thm_w
author_rank: Super Contributor
timestamp: February 25, 2019, 10:13:54 pm
content: 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.

author: floobydust
author_rank: Super Contributor
timestamp: February 25, 2019, 10:30:04 pm
content: 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.

author: thm_w
author_rank: Super Contributor
timestamp: February 26, 2019, 09:05:25 pm
content: Quote from: floobydust on February 25, 2019, 10:30:04 pmThanks, L1 and L2 meant lamp 1 and lamp 2, was confused with the L1.

author: Yansi
author_rank: Super Contributor
timestamp: February 28, 2019, 07:56:14 pm
content: 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!

author: NiHaoMike
author_rank: Super Contributor
timestamp: March 02, 2019, 02:18:56 am
content: Quote from: amyk on February 25, 2019, 03:04:06 amHere's another BBC Micro where the X2 cap apparently failed leaky and "cooked" for a bit rather than hard short with an arc flash.