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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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1st Oct 2020, 3:26 am | #1 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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Need help replacing a Rifa X2 capacitor.
I have a blown Rifa X2.
It reads PME 285 MB 40/11/56/b on the other side 275v~SH on the top 68n N3 What can I replace this with? It's discontinued. All I can find online is 100u M4 and i dont know what any of it means. Thanks. |
1st Oct 2020, 8:42 am | #2 |
Pentode
Join Date: Apr 2017
Location: South Coast, Western Australia.
Posts: 129
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Re: Need help replacing a Rifa X2 capacitor.
You should be able to salvage something similar out of a huge range of scrap electronic units, domestic or otherwise. There will be something useful around the mains input part of the PCB. It may not be RIFA but will have 'X2' written on it somewhere. 275V is important but any capacitance value near to 68 nanofarads, such as 100n will be fine.
BC |
1st Oct 2020, 12:47 pm | #3 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,203
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Re: Need help replacing a Rifa X2 capacitor.
If you salvage anything, make sure it's NOT a paper capacitor as they will do the same shortly, especially if used or old stock. Other X2 capacitors also deteriorate, but only with use and much slower and usually with a nicer failure mode.
It would be best to get a nice new X2 (X2 implies 275VAC or higher, 250VAC is old stock or cheap stuff) MKP (MKP means polypropylene dielectric instead of paper) capacitor of a reputable brand(Vishay, Epcos, Wima, Panasonic). In most cases 100n would be perfectly fine. If used as a series dropper, it should be replaced with an 68n type only. |
3rd Oct 2020, 2:19 pm | #4 |
Octode
Join Date: Nov 2010
Location: Cullompton, Devon, UK.
Posts: 1,435
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Re: Need help replacing a Rifa X2 capacitor.
These would be fine.https://www.ebay.com/itm/Lot-of-10-M...UAAOSwUQ5bvUTV.
john |
7th Oct 2020, 7:20 am | #5 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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OK there is a replacement part here since that Rifa is paper discontinued.
https://www.mouser.com/datasheet/2/2...275-961366.pdf If it says 68u I would rather replace with 68u, not a 100u Anyone know why this might have blown and could it have taken any other electronics with it? Do you know what the 40/110/56b means? Rated Voltage 275 VAC 50/60 Hz Capacitance Range 0.001 – 0.6 µF Capacitance Tolerance ±20%, ±10%, ±5% on request Temperature Range −40°C to +110°C Climatic Category 40/110/56 Approvals ENEC, UL, cUL What is climatic category guys? Is it important? |
7th Oct 2020, 8:02 am | #6 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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Re: Need help replacing a Rifa X2 capacitor.
0.0068 5.1 10.5 13.5 10.2 21 1,200 P276HL682M275 PME271MA4680M
0.0068 5.2 10.5 18.5 15.2 19 1,200 P276QE682M275 PME271M468M 0.068 7.8 13.5 18.5 15.2 5.6 1,200 P276QP683M275 PME271M568M which one is 68u |
7th Oct 2020, 9:19 am | #7 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,274
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Re: Need help replacing a Rifa X2 capacitor.
No need to over-think the specs here.
The one in your link is another paper capacitor, this will eventually fail. Better as others have said already is a Metallised Polypropylene Capacitor. Mouser stock code 98-683MKP275K 68nF 310VAC class X (across the line rated)
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Kevin |
7th Oct 2020, 9:25 am | #8 | |
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Location: Ipswich, Suffolk, IP4, UK.
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Re: Need help replacing a Rifa X2 capacitor.
Quote:
This is the same as 0.068uF (microfarad). To convert nF to uF move the decimal point three places to the left.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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7th Oct 2020, 2:39 pm | #9 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,203
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Re: Need help replacing a Rifa X2 capacitor.
On molded or epoxy potted paper capacitors, the climate category (and all other specs and markings) means that it will fail before its time and probably in a violent manner. No other way to say it. Just use an MKP.
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10th Oct 2020, 2:29 am | #10 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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ok so having it rated more at 300 vac is not bad?
it doesn't have to be a 275? are they designed to fail to protect other circuitry? is the voltage and the fared the only things i should be concerned with? frequency isnt an issue? thank you my issue is. is it supposed to fail? in a condition where there could be a safety issue (fire-explosion) is this sort of a fuse or no? this is in a controller board for a 220 cooktop. ok so the replacement is either P276QP683M275(1) or 683MKP275K now since IT IS called a safety capacitor. are they not supposed to fail? if this part is replaced with a part that doesn't fail, would it just throw an error on the board instead of blowing? sorry so many questions guys i am not a circuity person. i just want my cook top back i love it. |
10th Oct 2020, 9:42 am | #11 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,970
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Re: Need help replacing a Rifa X2 capacitor.
You are over thinking this. X2 capacitors made with a paper dielectric have a common failure mode whereby they fail short circuit and burn up. This is not a deliberate feature but a fault. Plastic film X2 capacitors do not fail in this way.
300V AC or higher is fine. Frequency is not an issue. |
14th Oct 2020, 7:01 am | #12 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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Re: Need help replacing a Rifa X2 capacitor.
Ok guys then I will be purchasing this one
683mkp275 the plastic MPK All the information you have given me is spectacular i appreciate it. I have a picture of the way the last one went on the board. I dont see any markings that signify + or - Any tips. |
14th Oct 2020, 10:00 am | #13 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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Re: Need help replacing a Rifa X2 capacitor.
There won't be any polarity markings. These are non-polarised capacitors with an AC voltage across them. You can fit them either way round.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
15th Oct 2020, 1:08 am | #14 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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Re: Need help replacing a Rifa X2 capacitor.
https://www.mouser.com/datasheet/2/2...71-1104176.pdf
Well this is the part I will be getting guys. Thanks I'll post what happens after install. |
15th Oct 2020, 11:40 am | #15 |
Moderator
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Location: Ipswich, Suffolk, IP4, UK.
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Re: Need help replacing a Rifa X2 capacitor.
On the first page of the data sheet it says they're not suitable for across the line (mains) applications.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
15th Oct 2020, 2:52 pm | #16 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 4,203
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Re: Need help replacing a Rifa X2 capacitor.
Or in other words: they aren't X2 capacitors. X2 (or X1 which is also good) is a hard requirement for mains suppressors.
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15th Oct 2020, 2:57 pm | #17 |
Moderator
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Location: Ipswich, Suffolk, IP4, UK.
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Re: Need help replacing a Rifa X2 capacitor.
A Mouser stock code was given in post #7.
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
16th Oct 2020, 8:43 am | #18 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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Re: Need help replacing a Rifa X2 capacitor.
well i almost made a mistake.
is there a cap plastic that does across the line and is 68n 275vac? |
16th Oct 2020, 8:55 am | #19 |
Dekatron
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 5,274
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Re: Need help replacing a Rifa X2 capacitor.
the one I said in Mouser is fine, its rated 'across the line'
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Kevin |
21st Oct 2020, 11:42 pm | #20 |
Triode
Join Date: Oct 2020
Location: Lakeland, Florida, USA.
Posts: 35
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Re: Need help replacing a Rifa X2 capacitor.
ill send them that this is the one i want in a .068nf 250vac
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