LCD Desktop Monitor Fading to White, then Black
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From: Mike Tomlinson on 2 May 2010 20:17 In article <ac15e6c5-a222-4cdb-a450-475b3d0a2e98(a)s29g2000yqd.googlegroup s.com>, saber850 <saber850(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...
From: saber850 on 2 May 2010 20:53 On May 2, 5:10 pm, Jeff Liebermann <je...(a)cruzio.com> wrote: > On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber...(a)yahoo.com> > wrote: > > >Both monitors are a Samsung SyncMaster 204B. > > Thank you for supplying the maker and model number. > > 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. > > My usual method is to replace *ALL* the large value electrolytic > capacitors. The labour is less to do it at one time, than to spend > any time finding which one or two is the culprit. Make sure you buy > 105C or 125C replacement caps as the 85c variety don't last. Larger > values and voltage ratings are fine, but watch out for package sizes > and lead spacing. > > -- > Jeff Liebermann je...(a)cruzio.com > 150 Felker St #D http://www.LearnByDestroying.com > Santa Cruz CA 95060http://802.11junk.com > Skype: JeffLiebermann AE6KS 831-336-2558 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?
From: saber850 on 2 May 2010 20:58 On May 2, 12:32 pm, Sjouke Burry <burrynulnulf...(a)ppllaanneett.nnll> wrote: > saber850 wrote: > > On May 2, 3:21 am, "N_Cook" <dive...(a)tcp.co.uk> wrote: > >> saber850 <saber...(a)yahoo.com> wrote in message > > >>news:2468c376-1884-4039-af3a-55c41cedb3c6(a)k29g2000yqh.googlegroups.com.... > > >>> Hi, > >>> My LCD desktop monitor has been exhibiting a problem for over 1 year. > >>> It is out of warranty and I would like to fix it. > >>> The problem is that the monitor displays the picture, and then > >>> gradually fades to white, and then gradually fades to black. > >>> The monitor does not exhibit the problem all the time. It comes and > >>> goes. I do not have a procedure which triggers the problem; it seems > >>> to be random. Sometimes it will behave this way for only a few > >>> minutes, while other times it will behave like this for weeks. > >>> I do not do anything to trigger the problem, other than have the > >>> monitor powered on. > >>> I have two of these monitors. I bought both monitors at the same time.. > >>> Both monitors are connected to the same video card (nVidia) via a DVI > >>> connection. Only one of the monitors exhibits the problem--the other > >>> continues to function properly. When the monitor exhibits the > >>> problem, I can swap the DVI cables and the other monitor continues to > >>> function properly. So I do not believe the problem is my video card or > >>> computer. > >>> I do not know of a method to get the monitor out of this problem > >>> state. I've tried cycling the power to the monitor, and I've tried > >>> rebooting the computer. Neither method fixes the problem. The only > >>> thing I can do is wait for it to fix itself. But eventually, it > >>> malfunctions again. > >>> A video of the problem occurring is available here: > >>>http://www.youtube.com/watch?v=W7YpFZVRjcE > >>> Best regards, > >>> Nick > >> Can you observe discrete jumps in the fade, ie stepped. > >> Is it a backlight problem? if so perhaps find the brightness control line to > >> the inverter and break there and add your own subcircuit perhaps. First > >> monitor that line as maybe a fault inside the inverter chip > > >> -- > >> Diverse Devices, Southampton, England > >> electronic hints and repair briefs , schematics/manuals list onhttp://diverse.4mg.com/index.htm > > > Thanks for the quick response. I do not observe discrete jumps in the > > fading--it seems very smooth to me. > > > I do not know if it is a backlight problem; how can I tell? > > If it is the backlight, you can still see a picture in strong > ambient light, try different viewing angles and light angles. > If you can still sortof see a picture, it is the backlight. > The slow fade suggests the invertor,or its powersupply circuit. 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?
From: saber850 on 2 May 2010 21:03 On May 2, 5:14 pm, Jamie <jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net> wrote: > hr(bob) hofm...(a)att.net wrote: > > On May 2, 9:22 am, saber850 <saber...(a)yahoo.com> wrote: > > >>On May 2, 9:40 am, Meat Plow <mhyw...(a)yahoo.com> wrote: > > >>>On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <dive...(a)tcp.co.uk>wrote: > > >>>>saber850 <saber...(a)yahoo.com> wrote in message > >>>>news:2468c376-1884-4039-af3a-55c41cedb3c6(a)k29g2000yqh.googlegroups.com... > > >>>>>Hi, > > >>>>>My LCD desktop monitor has been exhibiting a problem for over 1 year.. > >>>>>It is out of warranty and I would like to fix it. > > >>>>>The problem is that the monitor displays the picture, and then > >>>>>gradually fades to white, and then gradually fades to black. > > >>>>>The monitor does not exhibit the problem all the time. It comes and > >>>>>goes. I do not have a procedure which triggers the problem; it seems > >>>>>to be random. Sometimes it will behave this way for only a few > >>>>>minutes, while other times it will behave like this for weeks. > > >>>>>I do not do anything to trigger the problem, other than have the > >>>>>monitor powered on. > > >>>>>I have two of these monitors. I bought both monitors at the same time. > >>>>>Both monitors are connected to the same video card (nVidia) via a DVI > >>>>>connection. Only one of the monitors exhibits the problem--the other > >>>>>continues to function properly. When the monitor exhibits the > >>>>>problem, I can swap the DVI cables and the other monitor continues to > >>>>>function properly. So I do not believe the problem is my video card or > >>>>>computer. > > >>>>>I do not know of a method to get the monitor out of this problem > >>>>>state. I've tried cycling the power to the monitor, and I've tried > >>>>>rebooting the computer. Neither method fixes the problem. The only > >>>>>thing I can do is wait for it to fix itself. But eventually, it > >>>>>malfunctions again. > > >>>>>A video of the problem occurring is available here: > >>>>>http://www.youtube.com/watch?v=W7YpFZVRjcE > > >>>>>Best regards, > >>>>>Nick > > >>>>Can you observe discrete jumps in the fade, ie stepped. > >>>>Is it a backlight problem? if so perhaps find the brightness control line to > >>>>the inverter and break there and add your own subcircuit perhaps. First > >>>>monitor that line as maybe a fault inside the inverter chip > > >>>What brand/model monitor? > >>>What brand/model card with NVidia chip? > > >>>Does the monitor have a DSUB I/O? > >>>Does the video card have a DSUB I/O > > >>>The symptoms don't describe an inverter problem to me > >>>but rather an LCD matrix drive, possibley PSU derived. > > >>Both monitors are a Samsung SyncMaster 204B. > >>The video card is a ASUS EN7600GT. > > >>The monitors have 1 DSUB I/O port and 1 VGA I/O port. I've only ever > >>used the DSUB I/O. > >>The video card has two DSUB I/O ports. Each one is connected to a > >>monitor. > > >>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? > > >>Is the PSU typically isolated from other circuitry in the monitor such > >>that it can be replaced?- Hide quoted text - > > >>- Show quoted text - > > > I don't have any suggestions, but it is definitely Not the backlight. > > With a fading backlight the picture would just get darker and darker, > > there would be no video reversal such as shown in the video. > > Are you connected to a Laptop ? is power saving kicking in an option > available in your LCD if the battery is getting low? > Maybe we went over that already, I'm too tired to look back. No, this is one of my desktop monitors, and my desktop is not configured to sleep or hibernate. The second monitor which is connected to the same video card continues to function properly while the other malfunctions. So I don't think it's a problem of effect of the video card or computer.
From: saber850 on 2 May 2010 21:10
On May 2, 8:13 pm, Mike Tomlinson <m...(a)jasper.org.uk> wrote: > In article <2468c376-1884-4039-af3a-55c41cedb...(a)k29g2000yqh.googlegroup > s.com>, saber850 <saber...(a)yahoo.com> writes > > >The problem is that the monitor displays the picture, and then > >gradually fades to white, and then gradually fades to black. > > Erk. That video you put on Youtube is kinda creepy! Are you sure it's > not demonic possession? > > I don't think it's a backlight problem. It looks more like a contrast > issue. I have a similar Samsung monitor (SyncMaster 2343 widescreen) > with touch controls and It looks like yours has those too. In your > situation, the first thing I would do is whip the back off and > disconnect the touch control board from the main board and see if the > problem stops. I'm wondering if a "button" is stuck. > > Then I'd probably move to gently heating some of the chips, particularly > those on the back of the LCD panel, with a hairdryer to see if the fault > is temperature-related. > > I know you say you want to try and fix it, but if it's a panel fault, > the monitor's fit only for scrap. > > -- > (\__/) > (='.'=) Bunny's thinking about giving Windows 7 > (")_(") a go despite what he's said about it... Yeah, I was also a bit disturbed by the video when the picture's color inverts. I've changed my background so if I capture another video of the malfunctioning problem, it won't contain a person. If the problem were related to a "stuck" or "sticking" button on the face of the monitor, I'd expect the problem to exist all the time, or at least after I use the buttons. But neither is the case for me. The problem will start at a seemingly random time, and stop after a seemingly equally random duration. In particular, I rarely use the monitor's buttons except for power. I was also thinking about applying heat to the back of the monitor to see if that triggers the problem. If that triggers it, does that suggest a cold solder joint? Thanks for the info about the worth of the panel. |