Help with component ID - Page 1
Forum section: electronics / repair

author: tobor
author_rank: Contributor
timestamp: January 05, 2016, 04:40:28 am
content: Anyone know what kind of capacitor this is and what it's value would be?There are also a couple of others that look identical, but with a different number... 360J instead of the 1000K. Both have the 50(s) mark.Thanks for your help!

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 05, 2016, 04:54:50 am
content: What about the 360J? Sometimes "360" could mean 36 pF or 360 pF. (Is it 36 with "zero zeros" or just plain 360?)The capacitor type is poly film. But is it polyester or polyethylene?

author: natbuk
author_rank: Contributor
timestamp: January 05, 2016, 01:20:13 pm
content: It looks like a polystyrene cap.They're quite dear now, and not used that much.They tend to have very low distortion and good long-term and temperature stability.nat

author: Gyro
author_rank: Super Contributor
timestamp: January 05, 2016, 01:24:41 pm
content: +1 Polystyrene.

author: andybarrett1
author_rank: Regular Contributor
timestamp: January 05, 2016, 02:15:09 pm
content: +1 Polystyrene.

author: tobor
author_rank: Contributor
timestamp: January 05, 2016, 11:20:36 pm
content: Beauty! Thank you all! :-)

author: gadget73
author_rank: Regular Contributor
timestamp: January 06, 2016, 04:21:10 am
content: Is it actually bad? They're one of those cockroach components.

author: SeanB
author_rank: Super Contributor
timestamp: January 06, 2016, 08:00:57 am
content: Polystyrene, and always in pF, unless marked ( for really big ones) in uF. Easy to tell from the ends being conical and clear, along with the spindly leads. Note they really are heat sensitive, IR reflow will kill them, and soldering really needs either under 3 seconds per joint or a heat shunt on the leads. They melt at 70C.

author: tobor
author_rank: Contributor
timestamp: January 06, 2016, 04:55:23 pm
content: Thank you again! I don't know that they are bad... I don't have an LCR meter yet so I can't check that low a capacitance value. ESR value exceeds the range of my Blue ESR meter, but for all I know, that is perfectly normal for these.I found these in my 1985ish Acoustic Research X-06 receiver. I've found several failed electrolytic caps in it already, so I'm just replacing all of the original electrolytics (they're all Jamicon) with better quality Panasonic or Nichion caps.I won't be replacing these polystyrene ones unless I can prove they have a problem.Anyone know of a good reference book or website where I could try to ID unfamiliar components like this without having to pester you kind folks for the simple stuff?

author: cvanc
author_rank: Frequent Contributor
timestamp: January 06, 2016, 07:27:41 pm
content: Polystyrene caps are not known for going bad with age; yours are probably fine.But I can tell you that in addition to being heat sensitive (see earlier warnings about soldering technique) they can be damaged by many common solvents used in electronics. I once brought a radio station live studio to its' knees with an overzealous application of "Blue Shower" contact cleaner spray - it destroyed some polystyrene caps in about an hour and brought the mixing board down!

author: gadget73
author_rank: Regular Contributor
timestamp: January 07, 2016, 12:08:18 am
content: Excellent point about the heat. I had forgotten that. I bumped one once with a soldering iron, dead. It was in a 1950s German radio that I needed to extract a part from underneath it. All of the other polystyrene caps in that radio were and are still fine.