identify surface mount electrolytic capacitor - Page 1
Forum section: electronics / repair

author: fujimuji
author_rank: Newbie
timestamp: February 06, 2015, 04:19:09 am
content: Hello,I have a couple of caps (pictures below) from a ca. 1992 Toshiba MK2124 hard disk drive (HDD). I think the drive has failed due to electrolyte drying / leaking on these caps (occasionally get a pungent smell from them when the drive was trying to power up).I measured the ESR with an HP 4263B LCR meter at 100 Hz, shows Rs = ~ 2.6 kOhm (and actually was about that for any frequency). The reported series capacitance, on the other hand, falls with increasing frequency (perhaps that's expected with the way the LCR meter is measuring), starts at about 8 uF @ 100 Hz and ends up about 1.4 nF @ 100 kHz.1. I'm not really sure what the value of these caps are supposed to be, on the side is printed 100 with 6.3 V below (I guess 6.3 volt rating for a 5 V supply rail); you can see that in the first image below. On the end is stamped 27 with M3 below that, which is a bit hard to see, but in the 2nd image.2. I can't identify the type of package for these caps. They appear to be radial cans inserted into a black plastic rectangular cover. They are surface mount (the long leads you see in the pictures were soldered on so I could insert in the LCR meter). As they were on the board, they lie on their side, the two L shaped pins tucked under one end, and were soldered on 2 pads. In the 3rd image, you can see I was able to pull the can out of the plastic case / cover, and there is no markings on the side of the can.Any help, ideas, or suggestions is greatly appreciated.Thanks in advance.Side markings.End markings.Separated.

author: KJDS
author_rank: Super Contributor
timestamp: February 06, 2015, 08:05:24 am
content: That looks remarkably like a 100uF leaded cap that's been fitted with a onesie.

author: wraper
author_rank: Unknown
timestamp: February 06, 2015, 12:47:01 pm
content: 100uF 6.3V

author: fujimuji
author_rank: Newbie
timestamp: February 06, 2015, 02:08:41 pm
content: Quote from: KJDS on February 06, 2015, 08:05:24 amIs that a common fitting (the onesie)? Is there an industry term for it, searching "capacitor onesie" all I get is pyjamas with flux capacitors on them!Before posting here, I had searched for hours on digi-key and couldn't find anything that looked similar. I was hoping to replace them with identical looking parts, as long as they don't cost too much.I suspected it might be 100 uF given the size, but when the LCR meter was reading about 8 uF, I started to wonder if it's spec. was 10 uF; and then I thought if it follows the same 3 digit code as other electrolytic caps it would only be 10 pF (but that seemed rather unlikely).

author: fujimuji
author_rank: Newbie
timestamp: February 06, 2015, 02:15:14 pm
content: Quote from: wraper on February 06, 2015, 12:47:01 pmI'm inclined to agree, and now there's a consensus with what @KJDS said.

author: khaahk
author_rank: Contributor
timestamp: February 08, 2015, 03:05:01 pm
content: The round one might be crystal, not capacitor

author: fujimuji
author_rank: Newbie
timestamp: February 13, 2015, 08:56:33 pm
content: Quote from: khaahk on February 08, 2015, 03:05:01 pmWhy do you think it's a crystal?The round can fits in the black cover (i.e. they're the same component on the board). The picture below shows the view from the end, hopefully that clears things up.

author: wraper
author_rank: Unknown
timestamp: February 14, 2015, 11:10:22 pm
content: Quote from: khaahk on February 08, 2015, 03:05:01 pmDidn't know that cristals have "+" and "-"

author: khaahk
author_rank: Contributor
timestamp: March 07, 2015, 08:12:46 am
content: Didn't get that the plastic was only housing, then of course...