Any standard types in E-Caps for LCD screens ? - Page 1
Forum section: electronics / beginners

author: Sylvain
author_rank: Contributor
timestamp: March 13, 2013, 09:00:20 am
content: Hi all,I'm a freelancer in computer service and I occasionally recover some broken down LCD screens.Since I watch Dave's videos, I know that many of them are repairable by only replacing some electrolytic capacitors.I allready succesfully repaired one screen (and one mother-board) and I've got an other one on my bench.My problem is that I am far away from any electronic parts shop and I must purchase everything online. Those components are pretty cheap but postage costs aren't ...I would like to know if there is a bunch of references (10 ? 15?) I could buy hoping to be able to repair maybe 90% of the screens from 3 to 10 years ago.The first screen I repaired needed 1x1000µF 25V and 3x220µF 25V, and now the one on my bench needs 1x1000µF 16V (the 25V I've got won't physically fit) and 2x470µF 25V ...Last question : I used Panasonic Low ESR 105°C, is that a good choice ? Could you give me some other brands I can trust ?Thanks in advance for your help,Sylvain.

author: mariush
author_rank: Super Contributor
timestamp: March 13, 2013, 09:28:59 am
content: You need Low ESR capacitors, rated for at least 105c, and you should preferably use some with very big lifetime rating.Monitors don't have much air circulation in the back, they're pretty much sealed with minimal vents in the back so while running, the back side is always warm, so capacitors rated with a low number of hours @ 105c will slowly dry out and go bad sooner (but still we're talking about a couple of years or more of usage if they're quality capacitors)Good brands or capacitors ... Nichicon, United Chemi Con , Rubycon, Panasonic, Sanyo (now Suncon, they only make polymer capacitors under Sanyo/OS-CON brand)Panasonic FM, FR, FC for low uF value capacitors - FM and FR are some of the best, with 4000-10000 hours @ 105cNichicon HE, HM, HN series ( hm and hn are discontinued but should still be on the market)UCC KZE , KYRubycon ZL*You can also go to their sites and click on the "Series chart" pdf they should have and go to "Low impedance" section, the pick some with low impedance and big life rating. There are other series compatible with monitor usage but I don't know from the top of my head.Good stores to buy from : Digikey.com , RS-Components.com , Mouser.com , Farnell.com / Newark.com / Element14.com (same company, different sites for different continents)

author: alrj
author_rank: Newbie
timestamp: March 13, 2013, 10:20:57 am
content: You can also have a look athttp://www.badcaps.net/forum/showpost.php?p=2044&postcount=4for a list of known good brand/series.

author: Sylvain
author_rank: Contributor
timestamp: March 14, 2013, 08:33:41 am
content: Thank you for these 2 really precise answers !What I bought are Panasonic FC series, even if they are not the best, I think they will do the trick.Now my main question is still unanswered : can I buy a bunch of references in anticipation or will I be forced to order new références each time I have a new monitor to repair ?Thanks,Sylvain.

author: mariush
author_rank: Super Contributor
timestamp: March 14, 2013, 08:51:30 am
content: Generally, the most common used values are 470uF , 820uF , 1000uF. Some monitors would work with 25v rated capacitors, others need at least 35v but in most monitors 35v rated capacitors would still fit in the board space (diameter, height etc).Less often you'd see 330uF but in most cases you can use 470uF capacitors to replace those.It also makes sense to have a bunch of 10uF 50v , 22uF 35-50v, 33uF 35-50v , 47uF 25-50v, ... capacitors in this uF range are used on the power supply on the start up circuit near the transformer and they often dry out and make monitors not start.Other than this... 100uF 16v are commonly used on the display boards with voltage regulators (12v to 5v , 5v to 3.3v , 5v or 3.3v to 2.5v or 1.8v etc)... as these are commonly linear regulators they can be hot and dry the capacitors near them, which are generally 100uF and some voltage higher than the input, and 16v is generally enough.

author: mzzj
author_rank: Super Contributor
timestamp: March 14, 2013, 10:04:32 am
content: Quote from: mariush on March 13, 2013, 09:28:59 amYou might already know but for others: Be careful if buying Nichicon HM or HN series cheaply from ebay/surplus. Nichicon had widespread quality problems between 2002-2005 with these caps.And for general purpose caps(including most SMPS stuff) you should not buy the ultra-ultra-low-esr type caps. Quite offen these have shorter shelf-life and shorter lifetime in less demanding applications. Reasonably good for really high ripple current apps like CPU core voltage switchers, but I would not recommend for general use.Rumour is that these use water-based electrolyte that is more prone to pressure buildup. One tell-tale to avoid water-based electrolytic caps is to look for temperature rating: -55 Cel rated cap is probably organic electrolyte, -40cel rated are possibly water based ones.I have plenty of old stock but when I have to order new electrolytics these are my fafourites:Panasonic FCNichicon PWUnited Chemi-Con LXY or LXZ