LCD Desktop Monitor Fading to White, then Black
in [Repair]
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From: saber850 on 2 May 2010 21:12 On May 2, 8:17 pm, Mike Tomlinson <m...(a)jasper.org.uk> wrote: > In article <ac15e6c5-a222-4cdb-a450-475b3d0a2...(a)s29g2000yqd.googlegroup > s.com>, saber850 <saber...(a)yahoo.com> writes > > >As I mentioned in the OP, when the monitor is malfunctioning, I have > >swapped the DVI cables between the monitors. When doing so, the > >malfunctioning monitor continues to malfunction while the other > >monitor (the one which has never malfunctioned) continues to function > >properly. So from this, I believe the computer & video card are > >functioning properly. Am I making a valid assessment here? > > Yes. Sensible, logical fault-finding. > > >Is the PSU typically isolated from other circuitry in the monitor such > >that it can be replaced? > > It depends on the specific monitor. Some have an external PSU brick, if > yours are those then try swapping them over. If the PSU is internal it > will probably be on its own board which can be removed and swapped out. > > How old is the monitor? > > -- > (\__/) > (='.'=) Bunny's thinking about giving Windows 7 > (")_(") a go despite what he's said about it... This monitor does not have an external PSU brick; so I assume the PSU is internal. According to the following link, this monitor's power supply and inverter boards are integrated into one unit (http:// pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/). I purchased the monitor new in 2007.
From: Jeff Liebermann on 2 May 2010 22:46 On Sun, 2 May 2010 17:53:14 -0700 (PDT), saber850 <saber850(a)yahoo.com> wrote: >On May 2, 5:10�pm, Jeff Liebermann <je...(a)cruzio.com> wrote: >> This might be of interest: >> <http://pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/> >> <http://www.djhome.net/tips/samsungsyncmaster204T.htm> >> I've seen both problems on the bench with similar Samsung models. � >This is great info; thanks. The website links you found refer to the >problem as "flickering". Is that the condition my monitor has, given >the video I posted? No, it's not the same. What's probably happening is that as your power supply warms up, the cazapitors are starting to also get hot. My guess(tm) is that the power supply output voltages drop, causing the odd changes to white and black. The symptoms of having the wrong power supply voltage vary radically with the type of circuit and which capacitors are a problem. I've seen flickering, fades, time delayed sudden failure, smoke, fire, and most commonly, just plain no picture. Given a specific single component failure, it's possible to predict the symptoms. Given multiple partial failures, it's at best a guess. Open up the monitor (it's a royal pain), replace all the big caps whether they look bad or not, and live happily ever after. If you're into being sure, I suggest you look into purchasing or building an ESR (equivalent series resistance) meter, as you're guaranteed to run into this problem in other devices that use electrolytics (motherboards, TV's, power supplies, monitors, game boxes, router, etc). I use mine far too often. <http://www.ludens.cl/Electron/esr/esr.html> <http://www.anatekcorp.com/blueesr.htm> <http://www.flippers.com/esrktmtr.html> (I have this one) <http://www.midwestdevices.com/index.html> More good reading on LCD repair: <http://www.ccl-la.com/blog/index.php/category/monitor-repair/> Note how just about all the failures are electrolytic capacitors. Here's your Syncmaster 204 page: <http://www.ccl-la.com/blog/index.php/samsung-214t-repair/> Note the they're symptoms include a "dark picture". Hmmmm... -- 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: Jeff Liebermann on 2 May 2010 22:50 On Sun, 2 May 2010 17:58:59 -0700 (PDT), saber850 <saber850(a)yahoo.com> wrote: >If it is the invertor or the power supply circuit, would either be >worth repairing/replacing instead of replacing the entire monitor? Is >there any part of an LCD monitor whose expense would not justify its >replacement, and to simply replace the monitor as a whole? The Samsung SyncMonster 204/214 is all one big board. There are replacement boards available on eBay but they tend to have the same problem that you're trying to fix. Sending the monitor to the recyclers for such a simple problem will surely bring down upon your head the wrath of all repairmen, ecologists, and toxic waste handlers. To maintain your karma, you must at least make an attempt at repair. Incidentally, having two identical monitors is a bad idea. Sympathetic failure and contagious failure modes has been known to propagate between the bad monitor and the good. I would keep them apart just to be safe. -- 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: Mike Tomlinson on 3 May 2010 00:34 In article <h9est5dts76ogd6n7fktt0rrk4o4a79iud(a)4ax.com>, Jeff Liebermann <jeffl(a)cruzio.com> writes >Incidentally, having two identical monitors is a bad idea. Sympathetic >failure and contagious failure modes has been known to propagate >between the bad monitor and the good. Yeah, I know. Just had two Iiyama 20" TFTs (used side by side with a spanned desktop) fail on me. Expensive lesson. -- (\__/) (='.'=) Bunny's thinking about giving Windows 7 (")_(") a go despite what he's said about it...
From: Mike Tomlinson on 3 May 2010 00:58
In article <d4e144b2-9df6-4d9c-9ebb-9b5a1b3608c3(a)u7g2000vbq.googlegroups ..com>, saber850 <saber850(a)yahoo.com> writes >This monitor does not have an external PSU brick; so I assume the PSU >is internal. According to the following link, this monitor's power >supply and inverter boards are integrated into one unit Don't think so. The photos in your link show that the power board is separate. It would be unusual for the PSU and driver electronics to be integrated into a single board. It's also obvious that it's been designed down to the lowest price possible. >(http:// >pavel.kirkovsky.com/2009/03/samsung-syncmaster-204b-repair/). Ugh. The state of these caps. Samsung have skimped on the components and their users are now paying the price. Bad form. >I purchased the monitor new in 2007. I suggest as a first step you do what the link above suggests and replace the few caps indicated, and see how it goes. -- (\__/) (='.'=) Bunny's thinking about giving Windows 7 (")_(") a go despite what he's said about it... |