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This came up as a comment in other question I posted, but I thought it could be of use for someone else if posted separately.

I have an X2 cap rated ".47K275V~X2". Is that 0.47uF = 470nF? When I set my capacimeter wheel to the "200n" position and test the cap, it reads "40.2nF".

If I set the wheel to both 2m and 200u the capacimeter reads zero. When I go down to 20u it reads 0.04uF, then with 2u it reads .040uF, and with 200n, it reads 40.2nF. If I step down one more time to 20n, it reads 1.

Is the cap bad? Am I interpreting the rating on the cap case right?

Thanks!

Community
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jotadepicas
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  • @JRE I tried with 2m and 200u and it kept showing zero, when I go down to 20u it reads 0.04uF, then with 2u it reads .040uF, and with 200n, it reads 40.2nF. If I step down one more time to 20n, it reads 1. – jotadepicas Aug 20 '16 at 15:26
  • I assume it is out of circuit – Tony Stewart EE75 Aug 20 '16 at 15:37
  • @TonyStewart yes, it is out, I've desoldered it. – jotadepicas Aug 20 '16 at 15:39
  • Picture please. I would interpret 47K as 47nF. – user207421 Aug 21 '16 at 00:47
  • @EJP the cap is exactly like the one in TonyStewart answer below, see picture there. Also, AFAIK the letter K stands for "10% tolerance" and not "thousand". However let me know by the picture if you believe this is a 47nF cap and I'm looking it wrong. Thanks a lot! – jotadepicas Aug 21 '16 at 04:33

2 Answers2

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It appears to be defective and a common problem in Brazil too on coffee makers.enter image description here Perhaps line transients are common or the parts were fake Chinese clones and never good to begin with.

However, it should not affect function , unless noise suppression is critical and induces faults. This is not a common fault in Canada, but fake parts are common and easy to overlook.

Tony Stewart EE75
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  • Yes, precisely! I have also a Phillips coffee maker that went bad because of this. Why do you say it should not affect function? I understand the main function is to suppress noise, but for example in the coffee maker failure, replacement of the X2 cap solves it (for example: http://www.eevblog.com/forum/chat/another-polypropylene-capacitor-failure-senseo/). Could it be that the cap is serving another function in the circuit as well, or that by going bad it affects the circuit negatively? – jotadepicas Aug 20 '16 at 16:07
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    possibly...perhaps the water pump uses a diode series on AC line with a spring loaded solenoid and the lower impedance across the line assists the solenoid action. if that does expresso.... https://dicasdozebio.com/2014/01/19/dica-conserto-de-cafeteira-domestica-philips-senseo/ or check with distributor for quality recalls, defective parts used... – Tony Stewart EE75 Aug 20 '16 at 16:33
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The dot before 47 (.47) means 0.470 mikroFarads or 470 nF, K means +-10% The capacitor lost value and may be cannot work in circuit.

Juris
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