LCD Desktop Monitor Fading to White, then Black
in [Repair]
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From: Jeffrey D Angus on 11 May 2010 16:13 Jeff Liebermann wrote: > <jangus(a)suddenlink.net> wrote: >> Put the hole in the tip over the exposed lead, add a bit of >> solder then when it all melts, push the button on the vacuum >> and move the tool in a circular motion around the pin. Turn >> the vacuum off after you've removed the tool from the lead. > > Circular motion? Won't that tear up the pad? If I don't get all the > solder in the first suck, I add some more solder and/or flux, get the > joint hot, and suck again. Flux is the key as you can't suck dross. > Moving the tip around the joint just seems to make a mess and more > dross. I like to think of it as "circling the drain". Obviously you don't press down on the pad, but I've found that doing this circular motion makes all the difference in the world sucking up enough solder to get an empty hole and exposed lead. > The other Jeff. > (I haven't mailed the Symbol junk yet. Sorry.) No rush. Jeff -- �Egotism is the anesthetic that dulls the pain of stupidity.� Frank Leahy, Head coach, Notre Dame 1941-1954 http://www.stay-connect.com
From: Dav.p. on 11 May 2010 16:55 > Most LCD power supply boards are single sided with no plated through > holes. Those are the easiest boards to work with. When I recently ...and don't have a big ground area, for me can even work a poor 25W iron.. maybe but depends on how big the board, to be sure start with a 50W one that comes much useful for other works like recapping pc mainboards.. i say only to save some money..
From: saber850 on 13 May 2010 22:25 On May 10, 12:46 pm, saber850 <saber...(a)yahoo.com> wrote: > On May 9, 11:00 pm, "Dav.p." <davi...(a)tiscali.it> wrote: > > > > > > one did, while the "bad" monitor works fine (at least, so far). So > > > you say the bad mon. with the good power board i think... > > > > I'm confident that the problem is from the power board, and given this > > > ok, 1-0 for me... :) > > (ah it's a soccer score sorry..) > > > >both power boards to examine, I also noticed that the C110 and C111 > > >caps were replaced by Samsung when I sent the monitor in for repair > > > from what you noticed? The shining solderings? > > > >earlier this year (the last month of its warranty). I'll get the > > >specs of all caps today, find corresponding parts on DigiKey, and post > > >back here for confirmation. > > > i think is not so vital to find the specs, only take uF and V and order a good brand of low esr type. (105c) > > > >I will research this topic on the web, but are the Polymer caps > > >entirely superior to electrolyte ones? Are there drawbacks to polymer > > >caps? > > > As above i'm not an expert at all but i think.. with a good brand like Sanyo, Rubycon, Panasonic > > etc, you can go quiet and live life in peace for at least 3-4 years intense-use, > > it's a good idea replace all area's caps, to be sure.. like i said it's safer and instructive > > to test the 5v line output for instability, or the 12v if 5v is stable... but it is no so safe whitout > > precautions so it's up to you, if the boards stays screwed on the back and face outside is more > > safe. > > Yes, I'm confident the the problem is w/ the power board, since that's > the only thing that changed, and the problem followed it. The monitor > w/ the power board from the non-malfunctioning monitor has been > functioning properly for 24 hours. > > There are three reasons that I suspect the C110 and C111 caps were > replaced. The first reason is that all caps across both power boards > except those two have a hand-drawn black mark (line on the radius) on > top. Those two have slightly shinier solder. And there are small > scratches on the underside of the PCB around those caps' pins. > > As for testing the 5V or 12V lines, that's not easy because the boards > are not screwed down. There is a metal plate which sandwiches these > boards to the back of the panel, and which provides the mounting > point. So the "working" monitor stopped working today w/ the same symptoms. The only difference is that it has remained in this malfunctioning state all day--the longest I've ever experienced. I can't help but wonder if there's some truth to the theory that this is contagious. Fortunately, I ordered 2x the caps a couple days ago. So hopefully the problem is in fact the caps and I'll have both fixed soon.
From: Jeff Liebermann on 14 May 2010 00:10 On Thu, 13 May 2010 19:25:53 -0700 (PDT), saber850 <saber850(a)yahoo.com> wrote: >So the "working" monitor stopped working today w/ the same symptoms. I warned you. Unfortunately, this one good guess does not make up for all my other screwups. >The only difference is that it has remained in this malfunctioning >state all day--the longest I've ever experienced. I can't help but >wonder if there's some truth to the theory that this is contagious. This is the way rumors and religions are started. >Fortunately, I ordered 2x the caps a couple days ago. So hopefully >the problem is in fact the caps and I'll have both fixed soon. Good move by planning ahead. What else can go wrong.... Well, work on one monitor at a time, so that you have the other board as a sample for which way to insert the capacitors, and where the connectors and screws are located. It should be easy (famous last assumptions). -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 # http://802.11junk.com jeffl(a)cruzio.com # http://www.LearnByDestroying.com AE6KS
From: Mike Tomlinson on 16 May 2010 08:22
In article <6b0a157b-e045-40eb-a7a9-cee3092a7d92(a)h39g2000yqn.googlegroup s.com>, saber850 <saber850(a)yahoo.com> writes >Fortunately, I ordered 2x the caps a couple days ago. So hopefully >the problem is in fact the caps and I'll have both fixed soon. It'd be interesting to hear how you got on. -- (\__/) (='.'=) Bunny's thinking about giving Windows 7 (")_(") a go despite what he's said about it... |