Help identifying capacitor - Page 1
Forum section: electronics / beginners

author: stormy
author_rank: Contributor
timestamp: May 18, 2021, 01:45:22 pm
content: Hi there,This particular capacitor has some strange marking on it & I'm not too sure how to read them, please point me in the right directionThank youIC M F W.22K 630

author: CaptDon
author_rank: Super Contributor
timestamp: May 18, 2021, 02:19:20 pm
content: Some that I have seen that look similar would lead me to believe it is .22 microfarad at 630vac and is often seen across A.C. mains line voltage although if it were D.C. rated I would have expected to see a standard NEMA value of 600?

author: stormy
author_rank: Contributor
timestamp: May 18, 2021, 02:24:50 pm
content: Quote from: CaptDon on May 18, 2021, 02:19:20 pmThanks, yeah it is AC I think, on the primary side of this PSU:https://www.eevblog.com/forum/repair/ips-pec4074-psu-repair-for-sgi-indigo2-computer-(help-advice)/

author: stormy
author_rank: Contributor
timestamp: May 18, 2021, 02:30:10 pm
content: Does this look like a suitable replacement?https://www.mouser.co.uk/Cornell-Dubilier/Passive-Components/Capacitors/Film-Capacitors/_/N-9x371?P=1z0wqu1Z1z0z819Z1yp7zipZ1z0zlgf&Keyword=0.22uf+630v&FS=Truehttps://www.mouser.co.uk/datasheet/2/88/MPW-611137.pdforhttps://www.cde.com/resources/catalogs/WMF.pdf

author: bdunham7
author_rank: Super Contributor
timestamp: May 18, 2021, 02:40:15 pm
content: It is an Illinois Capacitor MWF series, metallized polyester, 0.22uF 630VDC 220VAC rated. The direct replacement would be the MWR series, but the polypropylene one you have selected should also work just fine in that application. Has this capacitor failed?

author: stormy
author_rank: Contributor
timestamp: May 18, 2021, 02:49:35 pm
content: At the moment it is suspected to be an issue (if you check my repair link) but yes I do need to test it. I don't have a capacitor tester so I'm thinking of just replacing it anyway.

author: Capernicus
author_rank: Frequent Contributor
timestamp: May 18, 2021, 02:52:33 pm
content: That had me stumped, i was thinking it was .22K hertz, (220 hertz) silly me.

author: stormy
author_rank: Contributor
timestamp: May 18, 2021, 03:06:43 pm
content: Would you guys know if the following would be a good tester? I really need to get myself something like this for transistors and caps. Any recommendations welcome.https://www.ebay.co.uk/itm/Portable-MK328-LCR-ESR-Tester-transistor-inductance-capacitance-resistance-meter-/203223888581?_trksid=p2349624.m46890.l49286

author: bdunham7
author_rank: Super Contributor
timestamp: May 18, 2021, 03:33:24 pm
content: Quote from: stormy on May 18, 2021, 02:49:35 pmI wouldn't think it too likely a failure point, but I don't know how it is used in that circuit. If shakalnokturn thinks it is a likely problem, you should look at it. You can test it for being shorted with an ohmmeter--it should read in the tens of megohms--but other than that, you really can't test it properly without a lot of equipment. If it performs some critical function where all of its parameters are important, you would need to test it for capacitance, ESR (very unlikely to be an issue, but you never know) and leakage at test voltage. If it is a legitimate suspect, it might be better to just try replacing it. I think a polypropylene replacement should be fine, but if you want an actual polyester replacement, use this:https://www.mouser.com/ProductDetail/CDE-Illinois-Capacitor/224MWR102K?qs=3tP%252BN51vMXc21aAPoP1Caw%3D%3D

author: stormy
author_rank: Contributor
timestamp: May 18, 2021, 03:36:58 pm
content: Much appreciated thanks!

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 18, 2021, 05:05:20 pm
content: Quote from: stormy on May 18, 2021, 03:06:43 pmI wouldn't spend that much on one (look at GM328 or LCR T4) but those little AVR based testers are a handy thing to have and would show the probable failure mode of this capacitor (reduced capacity).

author: james_s
author_rank: Super Contributor
timestamp: May 18, 2021, 05:13:12 pm
content: It wouldn't hurt to test it, but failure is very rare on that type of capacitor. It is certainly not one of the first things I would suspect.

author: bdunham7
author_rank: Super Contributor
timestamp: May 18, 2021, 05:16:43 pm
content: Quote from: stormy on May 18, 2021, 03:06:43 pmYes, as a basic tester for identifying parts and a quick go/no-go, they are OK. I have an earlier kit version and it works as advertised. Just make sure you get the ZIF-socket board with it as you will want both the ZIF and microclip features. Keep in mind that it won't fully characterize any components and really wouldn't be completely adequate for testing the capacitor in this thread. You might spot a defect or you might miss it. Still, at that price it is worth having.https://www.ebay.com/itm/113234059060?hash=item1a5d469f34:g:MggAAOSwDYBbj6FK

author: CaptDon
author_rank: Super Contributor
timestamp: May 19, 2021, 01:22:39 pm
content: I was thinking about that 630 thing this morning and remember now seeing 6.3vdc, 63vdc, and now this one at 630vdc. Years ago it seems that was not a common voltage rating for U.S. made capacitors. I do remember though all those years back seeing 6.3vdc and 63vdc stuff in European gear like Studer/Revox, Philips and others. Here in the states it seems 50, 75, and 100 was more common.

author: stormy
author_rank: Contributor
timestamp: May 20, 2021, 07:38:00 pm
content: Sorry guys one more cap I need some help to find a suitable replacement.I think it is a safety cap, 22uf? Searching on mouser:https://www.mouser.co.uk/Passive-Components/Capacitors/Safety-Capacitors/_/N-fb8xlZ1yzvvqx?Keyword=22uf+x2+mkt%2fsh&FS=True

author: BrokenYugo
author_rank: Super Contributor
timestamp: May 20, 2021, 07:47:05 pm
content: I read 0.022 microfarad, or 22 nanofarad if you prefer, class X2. You really have to pay attention to the leading zeros on this stuff, go back a bit farther and you'll even see picofarad range caps in RF circuits and whatnot referenced in microfarads.

author: madires
author_rank: Super Contributor
timestamp: May 20, 2021, 08:19:55 pm
content: Quote from: Capernicus on May 18, 2021, 02:52:33 pmThe upper case "K" denotes the tolerance of +/- 10%.