LCD Desktop Monitor Fading to White, then Black
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From: hr(bob) hofmann on 2 May 2010 16:43 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.
From: PlainBill47 on 2 May 2010 16:50 On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber850(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? The problem indicates an problem with the video controller IN THE MONITOR. The Samsung 204s (and other Samsungs) have a bad reputation for this reason. A slow fade to white can be a problem with the power to the LCD panel itself, a fast fade to black can be caused by the inverter. A slow fade to black MUST originate from the video controler. Open up the monitor, using all applicable precautions. On the video controller should be several three terminal devices, but labeled with a U number (as a hypothetical example, U404). Those are voltage regulators. It is remotely possible that one of those may be putting out an incorrect voltage. The last two digits in the part number will be the output voltage. Again, a hyprtetical part number - L117N33B is a 3.3 volt regulator. PlainBill
From: Jeff Liebermann on 2 May 2010 17:10 On Sun, 2 May 2010 07:22:40 -0700 (PDT), saber850 <saber850(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 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: Jamie on 2 May 2010 17:14 hr(bob) hofmann(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.
From: William Sommerwerck on 2 May 2010 17:14
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, of course -- that's Troubleshooting 101. What's going on is that the video information is being lost, and the pixel "twist" is being forced all the way one way, then all the way the other way. As to the cause... |