LCD Desktop Monitor Fading to White, then Black
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From: saber850 on 2 May 2010 03:05 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
From: N_Cook on 2 May 2010 03:21 saber850 <saber850(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 on http://diverse.4mg.com/index.htm
From: saber850 on 2 May 2010 03:25 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?
From: bill on 2 May 2010 06:35 On Sun, 2 May 2010 08:21:04 +0100, "N_Cook" <diverse(a)tcp.co.uk> wrote: >saber850 <saber850(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 I don't think it is a backlight issue My bet is a circuit problem with something common to all colors. The brightness increases to max, then it goes negative to black. Then it pops back to normal. A lot of monitors have everything wrapped up in one chip. Some ICs may drive the monitor directly. Look for unstable supply voltage. If the voltage is going on/off abruptly but has a big cap on the line that would explain it.
From: bill on 2 May 2010 06:39
On Sun, 2 May 2010 00:25:15 -0700 (PDT), saber850 <saber850(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. |