LCD Desktop Monitor Fading to White, then Black
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From: saber850 on 2 May 2010 08:21 On May 2, 6:39 am, b...(a)love.ranch wrote: > On Sun, 2 May 2010 00:25:15 -0700 (PDT), saber850 <saber...(a)yahoo.com> > 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? > > A backlight gives general brightness to an image. > if it is out, the video will still be there and u can see the image if > u shine a light on the screen - effectively replacing the backlight. > > your issue looks like the video is changing - not a backlight issue. > > check the PS voltages first. The problem isn't occurring at the moment. When it returns, I will try shining a light at the screen to determine if the problem is the backlight. Regarding the supply voltage: both monitors (as well as the computer itself) get their power from an APC UPS. When the problem returns, I will try using the outlet directly on the wall.
From: saber850 on 2 May 2010 08:24 On May 2, 3:05 am, saber850 <saber...(a)yahoo.com> wrote: > 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 One thing I forgot to mention about the video is that it is not demonstrating the typical "end" of this problem. Typically, the monitor fades to all white, then to all black (as captured in the video), and that's it; it will stay black. It typically does not cycle the way it does in the video, at least not indefinitely. It may cycle several times, but within 1 and ~5 cycles (usually just 1 cycle), it will stay in the "black" state.
From: saber850 on 2 May 2010 10:22 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?
From: David on 2 May 2010 11:46 >> >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 Does this monitor have buttons on the front to control brightness? Could one of those be stuck or shorted? David
From: Sjouke Burry on 2 May 2010 12:32
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. |