LCD Desktop Monitor Fading to White, then Black
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From: Jeff Liebermann on 4 May 2010 12:37 On Mon, 3 May 2010 20:18:13 -0700 (PDT), saber850 <saber850(a)yahoo.com> wrote: >So I tried various techniques to try reproducing the problem today, >all to no avail. I don't mean to be overly critical, but I think I see a problem. You remind me of something I had to deal with when training technicians in a past life. I referred to it as "Circle the wagons. The Indians are attacking". This was in reference to the tendency for some techs to march around the problem area, gain a little more insight, but burn huge amounts of time going literally in circles. The Indians never had a chance, after tiring their horses, by going in circles around the wagons. Both you and the attacking Indians would be far more effective with a direct assault on the problem. At some point, you will need to dive into the LCD monitor and get your hands dirty. No amount of additional insight or diagnostics are going to prevent this from happening. Even if you isolate the problem to a single capacitor and totally undestand the failure mechanism, you'll still need to crack the case and do the necessary parts replacement. Might as well get it over with now (before your horse gets tired). <http://www.ccl-la.com/blog/index.php/samsung-214t-repair/> -- Jeff Liebermann jeffl(a)cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
From: William Sommerwerck on 4 May 2010 12:57 >> So I tried various techniques to try reproducing the problem today, >> all to no avail. > I don't mean to be overly critical, but I think I see a problem. You > remind me of something I had to deal with when training technicians > in a past life. I referred to it as "Circle the wagons. The Indians are > attacking". This was in reference to the tendency for some techs to > march around the problem area, gain a little more insight, but burn > huge amounts of time going literally in circles. The Indians never > had a chance, after tiring their horses, by going in circles around > the wagons. Both you and the attacking Indians would be far more > effective with a direct assault on the problem. At some point, you > will need to dive into the LCD monitor and get your hands dirty. No > amount of additional insight or diagnostics are going to prevent this > from happening. Even if you isolate the problem to a single capacitor > and totally undestand the failure mechanism, you'll still need to > crack the case and do the necessary parts replacement. Might > as well get it over with now (before your horse gets tired). > http://www.ccl-la.com/blog/index.php/samsung-214t-repair Excellent points, that need to be repeated often. They're related to the issue of whether you're trying to figure out exactly what's wrong, or simply getting the unit working again. Often (too often), you have to abandon the analysis, and "dig in". My guess is that this problem is related to the power-supply voltages for the video driver circuits. Second guess would be a bad video driver. (I don't know whether it's a board or a single chip in this unit.)
From: saber850 on 4 May 2010 21:44 On May 4, 12:57 pm, "William Sommerwerck" <grizzledgee...(a)comcast.net> wrote: > >> So I tried various techniques to try reproducing the problem today, > >> all to no avail. > > I don't mean to be overly critical, but I think I see a problem. You > > remind me of something I had to deal with when training technicians > > in a past life. I referred to it as "Circle the wagons. The Indians are > > attacking". This was in reference to the tendency for some techs to > > march around the problem area, gain a little more insight, but burn > > huge amounts of time going literally in circles. The Indians never > > had a chance, after tiring their horses, by going in circles around > > the wagons. Both you and the attacking Indians would be far more > > effective with a direct assault on the problem. At some point, you > > will need to dive into the LCD monitor and get your hands dirty. No > > amount of additional insight or diagnostics are going to prevent this > > from happening. Even if you isolate the problem to a single capacitor > > and totally undestand the failure mechanism, you'll still need to > > crack the case and do the necessary parts replacement. Might > > as well get it over with now (before your horse gets tired). > >http://www.ccl-la.com/blog/index.php/samsung-214t-repair > > Excellent points, that need to be repeated often. > > They're related to the issue of whether you're trying to figure out exactly > what's wrong, or simply getting the unit working again. Often (too often), > you have to abandon the analysis, and "dig in". > > My guess is that this problem is related to the power-supply voltages for > the video driver circuits. Second guess would be a bad video driver. (I > don't know whether it's a board or a single chip in this unit.) Yes, I understand your point. I think I'm more apt to approach this cautiously for several reasons. One is that I don't have an urgent need to address the problem. This is partly due to my other monitor working fine, and also because the monitor does not malfunction frequently or for extended periods of time (a couple hours of downtime over several weeks). Another reason is that I'm not very knowledgeable or experienced on this type of problem, so I'm ramping up quite a bit. Yet another reason is that I'm a big proponent of measure twice, cut once. From what I've read, opening the case isn't simple, and will likely lead to blemishes. So I'd prefer to minimize the number of times I have to open it, which can be accomplished by having some confidence in the problem & solution. I understand that I won't know or understand every detail. But I don't think knowledge will hurt, and I'm not in a rush. So given this list, I find it reasonable to perform some extra diligence and learn a lot that I don't know, before digging in. I realize some people have suggested that the caps are a common problem w/ this monitor, but their problem doesn't seem to be the same as mine. And I'd prefer to avoid unnecessary de-soldering & soldering, given that I can actually make things worse. Given the symptoms of the problem and all that I've learned from this group and the web, I'm inclined to think the problem is the video board. But since I need to open the case to get the video board's part & rev numbers, I'll have a chance to inspect the caps before proceeding. Thanks to everyone for your help, I really appreciate it. I'll post back w/ my progress.
From: saber850 on 4 May 2010 23:15 On May 4, 9:44 pm, saber850 <saber...(a)yahoo.com> wrote: > On May 4, 12:57 pm, "William Sommerwerck" <grizzledgee...(a)comcast.net> > wrote: > > > > > >> So I tried various techniques to try reproducing the problem today, > > >> all to no avail. > > > I don't mean to be overly critical, but I think I see a problem. You > > > remind me of something I had to deal with when training technicians > > > in a past life. I referred to it as "Circle the wagons. The Indians are > > > attacking". This was in reference to the tendency for some techs to > > > march around the problem area, gain a little more insight, but burn > > > huge amounts of time going literally in circles. The Indians never > > > had a chance, after tiring their horses, by going in circles around > > > the wagons. Both you and the attacking Indians would be far more > > > effective with a direct assault on the problem. At some point, you > > > will need to dive into the LCD monitor and get your hands dirty. No > > > amount of additional insight or diagnostics are going to prevent this > > > from happening. Even if you isolate the problem to a single capacitor > > > and totally undestand the failure mechanism, you'll still need to > > > crack the case and do the necessary parts replacement. Might > > > as well get it over with now (before your horse gets tired). > > >http://www.ccl-la.com/blog/index.php/samsung-214t-repair > > > Excellent points, that need to be repeated often. > > > They're related to the issue of whether you're trying to figure out exactly > > what's wrong, or simply getting the unit working again. Often (too often), > > you have to abandon the analysis, and "dig in". > > > My guess is that this problem is related to the power-supply voltages for > > the video driver circuits. Second guess would be a bad video driver. (I > > don't know whether it's a board or a single chip in this unit.) > > Yes, I understand your point. > > I think I'm more apt to approach this cautiously for several reasons. > > One is that I don't have an urgent need to address the problem. This > is partly due to my other monitor working fine, and also because the > monitor does not malfunction frequently or for extended periods of > time (a couple hours of downtime over several weeks). > > Another reason is that I'm not very knowledgeable or experienced on > this type of problem, so I'm ramping up quite a bit. > > Yet another reason is that I'm a big proponent of measure twice, cut > once. From what I've read, opening the case isn't simple, and will > likely lead to blemishes. So I'd prefer to minimize the number of > times I have to open it, which can be accomplished by having some > confidence in the problem & solution. I understand that I won't know > or understand every detail. But I don't think knowledge will hurt, > and I'm not in a rush. > > So given this list, I find it reasonable to perform some extra > diligence and learn a lot that I don't know, before digging in. I > realize some people have suggested that the caps are a common problem > w/ this monitor, but their problem doesn't seem to be the same as > mine. And I'd prefer to avoid unnecessary de-soldering & soldering, > given that I can actually make things worse. Given the symptoms of > the problem and all that I've learned from this group and the web, I'm > inclined to think the problem is the video board. But since I need to > open the case to get the video board's part & rev numbers, I'll have a > chance to inspect the caps before proceeding. > > Thanks to everyone for your help, I really appreciate it. I'll post > back w/ my progress. I opened the case and analyzed all the caps--none are bulging or leaking/oozing.
From: Jeff Liebermann on 7 May 2010 00:25
On Thu, 6 May 2010 17:18:36 -0700 (PDT), saber850 <saber850(a)yahoo.com> wrote: >Thanks. Is there a particular brand of caps which is considered the >best? From my reading, I should stay away from CapXon (which is what >the Samsung monitor uses). Looking at my inventory, I've been using Panasonic-ECG, type A, Series NHG, with 105C temperature ratings. For example, the Digikey part number for 1000UF/16v is P5533-ND <http://industrial.panasonic.com/www-data/pdf/ABA0000/ABA0000CE26.pdf> <http://dkc3.digikey.com/PDF/US2010/P1643.pdf> If you want to avoid the problem entirely, search for Polymer Capacitors, which don't have any electrolyte. Fujitsu, UCC, and Oscon make those. <http://www.fpcap.jp/en/products/index.html> I just tried to fix a Samsung Syncmaster 192N monitor. I replaced 6 assorted CapXon electrolytics but the monitor doesn't work. My ESR meter is at home so I'll drag the pile home and report on the measured ESR values. A bit of Googling seems to indicate the CapXon are junk. More: <http://pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/> -- # 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 |