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Old 24th Feb 2017, 4:27 pm   #181
Humber888
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Default Re: Beware Rifa Class X Capacitors!

Just beware that C601 might originally have been a ceramic part but may have mutated over the years into a Rifa-like paper capacitor. I've seen this happen on the two HP5300 counters I've had. The ceramic version should be fine, but could be changed for a Class X disc ceramic if you feel inclined. At least it seems that your HP has not got a Schaffner IEC filtered inlet fitted. These often have Rifas inside.

Mike
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Old 25th Feb 2017, 12:21 am   #182
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Default Re: Beware Rifa Class X Capacitors!

The most rapid stink distribution rate must still be held by the one that went off in our vacuum cleaner. There is a photo of it earlier in this thread. The stink is powerful enough to get out of those potted inlet filters even if it takes brute force to do it.
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Old 11th Mar 2017, 6:27 pm   #183
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Default Re: Beware Rifa Class X Capacitors!

Further to comments made in my posting under 'Wanted' re. meter for HP436A power meter (since resolved):

Pics showing how these B.A.C.'s turned up in said power meters. The offenders have been prosecuted, found guilty and are currently being detained at my pleasure prior to subsequent termination (with extreme prejudice).

Guy
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Old 11th Mar 2017, 6:35 pm   #184
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Default Re: Beware Rifa Class X Capacitors!

A summary of two recent incidents of Rifa Class X capacitors having been found loitering inside a pair of HP436A power meters (with malicious intent).

Guy
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(oh, by the way: "B.A.C." is an abbreviation I've used to avoid plagiarising the term 'that capacitor'.)
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Old 11th Mar 2017, 8:18 pm   #185
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Default Re: Beware Rifa Class X Capacitors!

That was lurking in a heat shrink sleeve. Nasty!
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Old 11th Mar 2017, 8:40 pm   #186
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Default Re: Beware Rifa Class X Capacitors!

It's like gunpowder. Spread out it just goes off with a gentle flash. Encased in something to hold it together, you get a proper banger. With the Rifa capacitors, the addition of a small amount of heatshrink can greatly improve their surprise potential. Only the very top manufacturers went to this level of detail.

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Old 12th Mar 2017, 1:36 am   #187
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Default Re: Beware Rifa Class X Capacitors!

They also wrap fuses in heat shrink too.
When I see it I know that the equipment is likely to go bang.
It was bought at a high street store so do not feel guilty about buying stuff from overseas.
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Old 19th Mar 2017, 5:35 am   #188
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Default Re: Beware Rifa Class X Capacitors!

I have been aware of the RIFA CRAPacitor syndrome for many years, and still find examples of them doing a chernobyl.
Last year I bought a Tektronix 2430A scope, to add to my arsenal of test gear.
I brought it home, set it up and plugged in. Turned on and left it running for about 10 minutes.
Suddenly an enormous BANG followed by copious amounts of smoke being blown out of the unit (due to the force cooling fan).
I now pull everything apart first before powering up, if I suspect there may be a RIFA POS hiding within.
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Old 19th Mar 2017, 10:46 am   #189
Craig Sawyers
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Default Re: Beware Rifa Class X Capacitors!

Quote:
Originally Posted by Refugee View Post
They also wrap fuses in heat shrink too.
When I see it I know that the equipment is likely to go bang.
It was bought at a high street store so do not feel guilty about buying stuff from overseas.
Ugh. That is truly awful. What lack of pride in workmanship could give rise to something that looked like that inside.

Craig
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Old 19th Mar 2017, 12:17 pm   #190
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Default Re: Beware Rifa Class X Capacitors!

As I've almost certainly remarked before, those RIFA Capacitors are one of several makes/types of component I regard as 'replace on sight!'
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Old 19th Mar 2017, 3:32 pm   #191
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Default Re: Beware Rifa Class X Capacitors!

I think the heat shrink must have been fitted to get type approval without removing the glass fuse and fitting a sand filled one.
It did not improve the reliability of the item in any way.
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Old 19th Mar 2017, 4:21 pm   #192
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Default Re: Beware Rifa Class X Capacitors!

This thread gets progressively more grim every time I look at it.

Over the last two days I replaced the RIFA hand grenades in my HP 3312A generator (yes there was one lurking in the end) and my HP E3630A power supply. The latter I am very disappointed about because it's actually on the main board of the unit near the power switch. If that blew up it would make a right mess and require a new power switch which according to keysight would set be back about £50 in parts. Not only that it's the awkward pitch ones (20.5mm) which there appear to be no other vendors of at the specified 100nF and 275v. So I had to bodge a smaller one in.

I took them both out in the garden and lumped them to a pulpy death with my hammer. This, while completely pointless, made me feel slightly better.
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Old 19th Mar 2017, 8:03 pm   #193
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Default Re: Beware Rifa Class X Capacitors!

Hi, I've just found this one in an Akai GX 4000d tape recorder.

It's a "spark suppressor" across the microswitch that switches off the motor when the tape has run out.

I'm glad I found it before the magic smoke was released!

It's c902.
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Old 19th Mar 2017, 11:44 pm   #194
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Default Re: Beware Rifa Class X Capacitors!

Quote:
Originally Posted by Refugee View Post
They also wrap fuses in heat shrink too.
When I see it I know that the equipment is likely to go bang.
It was bought at a high street store so do not feel guilty about buying stuff from overseas.
Hi Refugee.

That's a worrying trend applying heat shrink sleeving to those Rifa caps and to glass cartridge fuses. I bet the manufacturer of the equipment didn't bargain for the mode of failure that those caps are infamous for. Seriously though, it's not a good idea to sleeve a glass mains fuse. It may be good for insulation purposes but creates a mini banger when the fuse fails violently. I remember these fuses used to shatter and in some case blast open the glass cartridge in the event of a severe overload due to a short in some older TVs. If the fuse was an HRC sand filled ceramic type then sleeving that would not be a problem.

The fuse in your pic had inflated the sleeving and it's snapped back. I bet that made a load bang.

Regards
Symon.
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Old 20th Mar 2017, 1:02 am   #195
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Default Re: Beware Rifa Class X Capacitors!

The biggest amount of stress released in that power supply was the low value limiting resistor that had blown the sleeve off completely.
The glass fuse had turned back into sand again. It was well and truly blown.
I bet the sleeve was only fitted to stop the sand getting onto the desk top leading to a claim from the customer as that was about the only "good" thing it did.
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Old 16th May 2017, 10:23 pm   #196
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Default Re: Beware Rifa Class X Capacitors!

Another explosion on my hands this evening courtesy of a non RIFA device. Repairing a PM3315. Managed to get the CPU online after isolating boards one by one. Turned out to be the vertical/analogue board was pulling the 5v rail down. Left it to burn in for a bit and check for hot spots on the living room table and sat down for a nice curry.

Next thing, fizz, loud bang and a smell like burned mulled wine and the mains filter had exploded:

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There's a RIFA X2 right after this just taunting me

This is being bypassed entirely and the RIFA X2 will be replaced with a cheap film capacitor.

Last edited by MrBungle; 16th May 2017 at 10:30 pm.
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Old 16th May 2017, 10:34 pm   #197
Philips210
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Default Re: Beware Rifa Class X Capacitors!

Hi

I wonder if that filter can contains a few Rifas after all?

Regards
Symon.

Last edited by Philips210; 16th May 2017 at 10:36 pm. Reason: correction
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Old 16th May 2017, 10:35 pm   #198
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Default Re: Beware Rifa Class X Capacitors!

Most likely. Destructive tear-down required
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Old 16th May 2017, 11:42 pm   #199
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Default Re: Beware Rifa Class X Capacitors!

I was going to widlarize it tomorrow so I'll take some photos
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Old 22nd Jul 2020, 2:48 am   #200
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Default Re: Ferguson IKC2. Something went BANG!

I have smelt one that went off in a vacuum cleaner. The motor keeps going and stirs the smoke up big time.
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