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-   -   What to replace a RIFA X2 with? (https://www.vintage-radio.net/forum/showthread.php?t=145591)

WaveyDipole 11th Apr 2018 11:17 am

What to replace a RIFA X2 with?
 
I recently received a 'capacitor replacement kit' for the PSU in my BBC Micro. The kit contains two RIFA X2 type capacitors. We are all aware of the explosive nature of RIFA caps. The Electrolytics are Rubycon and Suntan, both 105deg. I know Rubycon are Ok but I have never heard of Suntan? Anyway, back to the RIFA and my question is whether to use these two replacements (I rather suspect this would not be advised) or if not then what to use as replacements?

A quick search on eBay brought up names like Iskra, Epcos, Kemet, even WIMA and a few unknowns, including some that looked very much like the aforementioned RIFA. I believe somebody on another thread also mentioned Panasonic. The only one I'm not familiar with is Iskra. Any recommendations?

tony brady 11th Apr 2018 12:50 pm

Re: What to replace a RIFA X2 with?
 
Epcos are good, never had a problem with them.

Kemet & Wima also should be good. Iskra was a supplier of cheap parts

Al (astral highway) 11th Apr 2018 1:12 pm

Re: What to replace a RIFA X2 with?
 
Quote:

Originally Posted by WaveyDipole (Post 1034211)
. The kit contains two RIFA X2 type capacitors. We are all aware of the explosive nature of RIFA caps.

Hello, I'm saying this with a friendly tone, but I can't agree with this generalisation.

RIFA is a brand of a company that exists now and it isn't fair or reasonable to use a public forum to cast doubt on the integrity of a whole product line without justification or a right of reply.

I don't have any affiliation with the company, but it just seems like a sound principle. Here is my reasoning:

*I use current generation X1 and X2 metallised polypropelene RIFA caps in simple on-sight fixes with no problems. They are just fine.

*I also use pulse polypropelene capacitors by EVOX RIFA. They are very reliable.

* I use their big, low-ESR electrolytics...These are excellent.

* and recently, I've used one of their AC motor start capacitors, a pull from a consumer electric fan.

Here you go... some product lines!

http://www.kemet.com/Film_Capacitors

Quote:

Originally Posted by WaveyDipole (Post 1034211)
A quick search on eBay brought up names like ... Kemet,

Kemet is effectively EVOX-RIFA. If you ask for online data sheets for RIFA products, you'll get a Kemet page.

Cheers!

*After-note. Suntan is a familiar brand, pretty sure I've seen them in computer SMPS that I've found junked in the street.

Sideband 11th Apr 2018 1:24 pm

Re: What to replace a RIFA X2 with?
 
Yes it's like Wima of the old days. These were always a change-on-site capacitor. Now however their X and Y poly....whatever are absolutely fine and as good as any other brand. Likewise modern Rifa as far as I know are just as good as Kemet, Epcos and Vishay. They have come a long way since the Rifas of many years ago....and don't forget that the old Rifas that fail now are way past their design life.

If the Rifas supplied in your kit are the old semi-transparent type then they could be subject to failure (as it's known that the casing crystalises and allows moisture in). If they are a more modern plastic type then they are probably fine.

Maarten 11th Apr 2018 1:38 pm

Re: What to replace a RIFA X2 with?
 
I would use any MKP X2 capacitor. Just no paper capacitors. That includes the infamous RIFA clear potted types and WIMA MP3 types that behave in the same way - even if they last slightly longer.

On the other hand, I would steer clear of any RIFA foil capacitor, not because I'd think they break as fast as their paper types but because their manufacturer has very bad judgement when it comes to maintaining and marketing their product lines. They may still break before the competitors equivalent, though. I would use their electrolytics but that isn't relevant in this case.

(RIFA in this case meaning former RIFA product lines even if they are labeled Evox or Kemet, former AVX foil capacitors are also marketed as Evox or Kemet)

Refugee 11th Apr 2018 1:50 pm

Re: What to replace a RIFA X2 with?
 
These are one component that needs a date that is human readable.
They have a shelf life that adds to the service life.
15 years is about right but allow 5 years for storage.

WaveyDipole 11th Apr 2018 2:01 pm

Re: What to replace a RIFA X2 with?
 
Quote:

Originally Posted by astral highway (Post 1034238)
Hello, I'm saying this with a friendly tone, but I can't agree with this generalisation.

I take your point about generalization. The comment should have perhaps been specifically applied to X2 caps with clear case which seem to be frequently the subject of discussion when they blow apart in older equipment leaving a nasty smell and gunge. RIFA may well make other products which are absolutely fine. BTW, I will porbably replace the Suntan with a Panasonic.

Quote:

Originally Posted by Sideband (Post 1034243)
If the Rifas supplied in your kit are the old semi-transparent type then they could be subject to failure (as it's known that the casing crystalises and allows moisture in). If they are a more modern plastic type then they are probably fine.

The caps that I have received are indeed the transparent types which look just like ones that I have occasionally seen bulging and cracked. This is why I was unsure about fitting them. Both are rated 275v AC, one is 100n and the other 10n, and have the following printed on them: PME 271 M, also followed by 40/110/56/B. PME271 seems to refer to Metalized paper caps, apparently made from "Self-extinguishing UL 94V-0 encapsulation material" according to the datasheet. I take the point regarding ageing and these are new, but I am still unsure.

UPDATE: just seen the comments posted in the meantime on RIFA clear potted caps and MKP (posts 5 & 6). Thanks. This is starting to look as I suspected. I will need to buy something else, which now means 3 out of the 4 caps in the kit probably want replacing!

Diabolical Artificer 11th Apr 2018 4:59 pm

Re: What to replace a RIFA X2 with?
 
" it isn't fair or reasonable to use a public forum to cast doubt on the integrity of a whole product line without justification" Eh? We've been dissing Rifa caps here on this forum for years Al, not to mention they've had a pounding on other forum's and Youtube.

Have used Vishay F339X1 cpas in the past to replace Rifa's - http://uk.farnell.com/vishay/f339x13...rad/dp/2546764

Suntan caps are ok in my experience, been using their green poly caps for years.

Andy.

MrBungle 12th Apr 2018 9:17 am

Re: What to replace a RIFA X2 with?
 
To be honest RIFA caps are absolutely fine as long as you replace them every few years. Same with Schaffner filters. I actually occasionally replace them with the KEMET variety of the same capacitors. I have a big bag of them here!

I buy the ones from here usually if I want cheap replacements: https://www.bitsbox.co.uk/index.php?...ex&cPath=65_81

Suntan are pretty good. I always use their NP0 ceramics and have used their X2's before.

Radio Wrangler 12th Apr 2018 9:29 am

Re: What to replace a RIFA X2 with?
 
Considering what those Rifa capacitors have done to US, I fee quite justified in anything I choose to say about them.

The boss' pet Tek2465 went up in a blaze of smoke and glory, stinking out the building. Rifas! So I ordered some X2 parts of the appropriate ratings from Farnell, checking that the capacitors were some other make and were reassuringly not golden. What turned up? Rifas! I swore.

David.

MrBungle 12th Apr 2018 9:51 am

Re: What to replace a RIFA X2 with?
 
Yep. They're still RIFAs even though they are KEMET branded now. check pictures on RS:

https://uk.rs-online.com/web/p/paper...itors/4148689/

Al (astral highway) 12th Apr 2018 10:24 am

Re: What to replace a RIFA X2 with?
 
Quote:

Originally Posted by Diabolical Artificer (Post 1034303)
Eh? We've been dissing Rifa caps here on this forum for years Al, not to mention they've had a pounding on other forum's and Youtube.

Hey Andy, yes! I'm aware, I've been here the whole time! I have experience of the troublesome ones.

It doesn't change my viewpoint. There's a class of RIFA caps that has caused a stink and a ton of woe. There are other products that are excellent. Simples.

Not everyone will agree with the big picture view of the company that now exists as EVOX-RIFA (Kemet, distributor), but I got a strong impression that some people weren't even aware that the company embodied these brands. And, as I say above, some of them are (now) excellent.

A couple of days ago, in this thread:

https://www.vintage-radio.net/forum/...d.php?t=145449

Rusell W_B, a power RF engineer, said in post no 19 that in the 90's, they replaced all the 1200V and 200V electrolytics on their modulator valve switching decks with EVOX-RIFA electrolytics and never had a problem with them. That is a tough old role, and it proves real quality.

I hope the forum is elastic enough for people to speak out when they think something isn't quite on the money, and for a friendly flow of ideas to happen.

Al (astral highway) 12th Apr 2018 10:27 am

Re: What to replace a RIFA X2 with?
 
Quote:

Originally Posted by Radio Wrangler (Post 1034492)
Considering what those Rifa capacitors have done to US, I fee quite justified in anything I choose to say about them.

The boss' pet Tek2465 went up in a blaze of smoke and glory, stinking out the building.


That's more than annoying. I get where you're coming from, David, and I can imagine that people with such strongly memorable experiences, with sensory overload and interruption to workflow, might become averse to the whole brand!

Refugee 12th Apr 2018 7:52 pm

Re: What to replace a RIFA X2 with?
 
I had one go off in the vacuum cleaner. It set the fire alarm off.
There is a photo of all the smoke in another thread here.

bikerhifinut 12th Apr 2018 8:42 pm

Re: What to replace a RIFA X2 with?
 
It strikes me, viewing from the "cheap seats" that to tar a manufacturer with a brush because of a single particular type and construction of capacitor from the past is more than a little unfair.
OK these particular X2 construction jobs appear a bit flaky but I have used EVOX RIFA polypropylene film caps for years with total confidence in high voltage valve gear as DC blockers etc.
Likewise the poor opinion of WIMA caps seems to be based on items that were made in the past and again I happily use their polyprop and polyester film capacitors.
I wouldn't junk those Suntan branded electrolytics out of hand, I haven't yet used them but they've been around as budget price capacitors for a while and others seem happy with them.

Just my inexpert opinion.

A.

Radio Wrangler 12th Apr 2018 10:17 pm

Re: What to replace a RIFA X2 with?
 
Quote:

Originally Posted by astral highway (Post 1034509)
There's a class of RIFA caps that has caused a stink and a ton of woe. There are other products that are excellent. Simples.

Not quite so simples. Did not the wise man say that you're only as good as your worst product?


Reliant made the Scimitar which was supposed to be quite decent in its day, but does anyone think of it when their name comes up?

David

McMurdo 12th Apr 2018 10:43 pm

Re: What to replace a RIFA X2 with?
 
Suntan are supplied by Conrad/Rapid. They do a wide range of 105deg low impedance electrolytics and various other bits.
I haven't had a problem either but I would rather use something more upmarket for a paid job.

Maarten 13th Apr 2018 12:29 am

Re: What to replace a RIFA X2 with?
 
Quote:

Originally Posted by astral highway (Post 1034510)
That's more than annoying. I get where you're coming from, David, and I can imagine that people with such strongly memorable experiences, with sensory overload and interruption to workflow, might become averse to the whole brand!

I think my rationalisation is perfectly workable. If a product line manager, sales staff, etc. have that bad a judgement (or have a long standing bet with who knows), you never know what you get when you do business with such a manufacturer. There is no technical case to be made whatsoever to market a more expensive, less reliable and very replaceable by about any low end MKP, paper capacitor. The niche markt for paper capacitors exists but does not and should not inlude types as this that have better equivalents. Philips figured this out in the late 1950's and phased out all 'simple' paper capacitors over the roughly 25 years following. It hasn't been necessary to manufacture capacitors like this for 40 years.... No serious manufacturer can not know this.

I use that as a rationalisation to steer clear of any former RIFA paper or plastic foil capacitor product line. When forced, I might buy their electrolytics and I would buy Kemet or Evox products from other former manufacturers if an alternative isn't quite feasible. If they work that hard to tarnish their reputation, they must not want me as a customer.

P.S. I know Wima also still has an MP3 line, which is better than Rifa's but only slightly. If their MKP types weren't as proven as they are and if they would still market their MP series as strongly as Rifa, I would steer clear of them too. They just might be the company Rifa would have that long standing bet with, I speculated about...

Diabolical Artificer 13th Apr 2018 7:20 am

Re: What to replace a RIFA X2 with?
 
"I hope the forum is elastic enough for people to speak out when they think something isn't quite on the money, and for a friendly flow of ideas to happen." You have a point Al, I was a bit surprised at the strength of feeling behind your point though and the fact you havn't mentioned it before on the "Smoking Rifa's" thread. I was just giving you a bit of friendly gyp BTW, so no hard feelings : ) David and Maarten have a point too, I feel like that bloke off the Fast Show now : )

Anyhoo, this is off topic. I wonder why the kit put togetherer's used them in the first place, it's not as if they're that much cheaper than an equivalent with a better rep. The audio lads at Hifi Collective are almost wistfull about them - https://www.hificollective.co.uk/com...apacitors.html , maybe they were included for their tonal qualities? Might be an idea to hold on to your old RIFA's, might be worth a bob or two in a few years.

Lastly on the main product page - https://www.hificollective.co.uk/com...a-pme271m.html it says this - " Evox Rifa are the last remaining manufacture of metallized paper capacitors." This may be indicative.

A.

Radio Wrangler 13th Apr 2018 8:43 am

Re: What to replace a RIFA X2 with?
 
Should we now start a rumour that Rifa metallised paper capacitors sound really good for a bit of fun?

David


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