What do this cap's identifications mean - Page 1
Forum section: electronics / general

author: cowasaki
author_rank: Frequent Contributor
timestamp: September 03, 2022, 01:18:09 pm
content: Just ordering some parts for my HP3582A and I missed a few bits so need to order them too...This part is confusing meI took it as a small cap (and it doesn't appear to be polarised) but it says (it's tiny maybe just over a cm - images via my scope)2nd picture is the board it is off. There are 5 of these on the board but I have yet to take the others off.KEMET2R2uF. - The value but 2R2uF ?? 2.2uF?? what's with the R?35V10% - obviously 35 volts and 10% tolerance82041M - probably date code of 41day of 82 or something+T110 - No ideaAny ideas?

author: cowasaki
author_rank: Frequent Contributor
timestamp: September 03, 2022, 01:41:35 pm
content: The power board is a little different in the service manual but having just found the board (the service manual is rather large) that can is shown as 4u7 so I'm guessing that my guess of 2u2 was probably correct for my revision board and it is a non polarised cap. I tests as a 2uF cap as well so I've stuck it back in in the same orientation just in case.

author: SeanB
author_rank: Super Contributor
timestamp: September 03, 2022, 01:45:55 pm
content: 2.2uF 35V glass seal tantalum capacitor. No need to replace, as they will literally last for a few decades, seeing as they all come space rated from Kemet. Just check if they are short circuit, but otherwise they last forever.

author: Gyro
author_rank: Super Contributor
timestamp: September 03, 2022, 01:46:55 pm
content: Yes, those are 2u2 35v (dry) Tantalums. They're hermetic, unlike the bead ones, so are generally very reliable![Ed: Snap!]

author: TimFox
author_rank: Super Contributor
timestamp: September 03, 2022, 02:09:49 pm
content: "R" in the middle of an expression such as 2R2 indicates a decimal point. It is a convention, common in military specifications, and is far easier to read on a small component than a ".".

author: Stray Electron
author_rank: Super Contributor
timestamp: September 03, 2022, 02:18:40 pm
content: Quote from: TimFox on September 03, 2022, 02:09:49 pmCorrect. and only some countries use "." as the Radix point so the manufacturer decided to make the marking more specific. See Wikipedia <https://simple.wikipedia.org/wiki/Radix_point>

author: themadhippy
author_rank: Super Contributor
timestamp: September 03, 2022, 03:17:53 pm
content: QuoteRuF = how a dog feels if they eat it

author: cowasaki
author_rank: Frequent Contributor
timestamp: September 03, 2022, 03:38:34 pm
content: Thanks everyone, it was as I surmised except for the tantalum part. Yes the one I tested was still in spec. I will lift one leg and check each of the remaining ones. That particular power board appeared to be working with the ones further down stream appearing faulty (probably due to failing dual axial caps - all of which are out of spec by an order of magnitude or more).I've got an order pending with JLPCB & PCBway..... I'l decide when they get back to me. I quickly designed a small adapter board to turn two radial caps into a dual axial cap so it's all coming together.10 boards with 14 adapters on each..... I'll have some left if anyone else needs any :-)The idea is to fit them so they are lying down and using this board it will then fit into the space that the original dual axial cap went.

author: tooki
author_rank: Super Contributor
timestamp: September 03, 2022, 09:54:12 pm
content: Quote from: Stray Electron on September 03, 2022, 02:18:40 pmDon’t put angle brackets around a URL: that prevents the forum software from automatically turning it into a clickable hyperlink.https://simple.wikipedia.org/wiki/Radix_pointHowever, I think the full English articlehttps://en.wikipedia.org/wiki/Decimal_separatoris actually more relevant.