lcd screen failure symptoms and resolutions made in china
3. #If all the above is OK, measure the LVDS voltage value. Under normal conditions, the LVDS signal’s RX+/ RX-voltage value is about 1.2v, and RX+/ RX-difference value is about 200mV. At the same time, the resistance of the LVDS signal to ground and the resistance between the LVDS signal pairs can be measured (100 ohms). If there is an exception to these values, try replacing the ASIC.
1. #Confirm whether the COF on side X is hot compared with the normal temperature, whether there is fracture or wear crack, and whether the COF is burnt.
4. #Determine whether the gate IC is OK. There is a signal test point on the back of COG-IC, and the green paint can be scraped for measurement confirmation; If there is a gate IC problem, which IC fault can be confirmed. The confirmation of gate IC fault is only for analysis when you are interested, and this method is not recommended.
3. #Confirm whether the RSDS value is correct, normal RSDS is about 1.2v, and the signal difference is about 200mV; At the same time, we can confirm the resistance between RSDS signal (normal 100 or 50 ohms) and RSDS resistance to ground. If the voltage is NG, check if the ASIC and X-COF are hot.
1. #Adjust the VR knob to see whether it can be adjusted and whether the screen performance changes. At the same time, confirm the VCOM value (about 7v), if NG, replace the VR knob.
2. #Confirm VGH/VGL voltage (about 30V VGH and -6v VGL), and confirm whether it is DC/DC loop NG or COF IC NG; The corresponding resistance of disconnected VGH and VGL can determine whether it is a DC/DC problem or a COF-IC problem. If it is DC/DC NG, try to replace UP1 or confirm whether the corresponding transistor is OK.
3. #If the whiteness changes significantly with the view Angle, and above 1&2 analysis is all OK, polarizer NG or CELL NG can be basically determined.
2. #Confirm whether there is 12V input, if not, confirm whether the connector is OK, and confirm the resistance value of 12V voltage to earth; If conn. NG, change conn.; If 12V is short-circuited to the ground, disconnect FP1 to determine the short-circuiting circuit.
3. #Confirm whether FP1 is open; if open, replaces fuse. If the 12V accessory of this model has a reverse diode, confirm the continuity of the diode and check whether it is burnt.
B. Confirm VAA resistance to ground at VAA test point of R plate (A short circuit usually occurs), disconnect the corresponding capacitance of the following 3 COF, and confirm VAA resistance to the ground again. If OK, replace the capacitor, if NG, replace COF. If VAA is still NG, confirm DC/DC loop as all models.
3. #Shaking module, if vertical lines disappear or reappear, then it can be judged that the possible cause is COF pin broken, and the crease should be found under the OM microscope.
4. #Press the LCD glass side of the panel, if the vertical lines disappear or reappear, it can be judged that the cause of poor contact, OM checking should be able to find the poor contact.
Lamp line is broken Replace the lamp tubing Depending on the backlight structure, there will be different results. The failure of the performance may be a point-off, or it may be a backlight with a dark band.
Lamp line is broken Reconnect / replace lamp tubing Depending on the protection status of the power board, it may be a backlight with a dark band or it may be a point-off.
3. #Disassemble the backlight, confirm whether there is a short circuit with broken skin on the lamp strip, whether the plug of the lamp strip is fully integrated with the socket, whether the pin is aslant/off, whether the connector is off, and whether the LED bead is black and injured.
4. #The fault of the product is basically caused by the above reasons. If the appearance is fault-free, the lamp bar can be crossed to confirm whether the phenomenon follows the lamp bar, or the voltage of the lamp bar and the conduction condition between the lamp beads can be measured.
The above is the full text of LCD screen failure repair guide, we hope it is helpful to you. If you need to buy LCD and find a reliable LCD supplier, we suggest you to read our other great blog – How to find a reliable LCD supplier.
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Troubleshooting CRTs versus LCDs begins with similar steps, but diverges due to the differing natures of the two display types. The first troubleshooting steps are similar for either display type: power down the system and display and then power them back up; make sure the power cable is connected and that the outlet has power; verify that the signal cable is connected firmly to both video adapter and display and that there are no bent pins; verify that the video adapter is configured properly for the display; try the problem display on a known-good system, or try a known-good display on the problem system; and so on. Once you"ve tried the "obvious" troubleshooting steps, if the problem persists, the next step you take depends on the type of display. The following sections cover basic troubleshooting for CRTs and LCDs.
CRTs seldom fail outright without obvious signs, such as a loud snap or a strong odor of burning electrical components. Most CRT problems are really problems with the power, video adapter, cable, or hardware/software settings. To eliminate the CRT as a possible cause, connect the suspect CRT to a known-good system, or connect a known-good display to the suspect system. It is worth noting, that older CRTs eventually wear out, and starts dimming. Common signs of a weak CRT are a dim picture, dysfunctional brightness and/or color controls, image smearing at high brightness, and in color CRTs, a tint towards a single color (Red Green Blue)
If the CRT is the problem, it is often not worth repairing. If the CRT is out of warranty, parts and labor may cost more than buying a new CRT, which also gives you better specs and a warranty. About the only CRTs we"d even consider repairing out-of-warranty are high-end 21" or larger models, and even there the economics are dubious.
Never disassemble a CRT. At best, you may destroy the CRT. At worst, it may destroy you. Like televisions, CRTs use extremely high voltages internally, and have large capacitors that store that energy for days or even weeks after the CRT is unplugged. Robert once literally burned a screwdriver in half when working inside a color television that had been unplugged for several days. Also, the large, fragile tube may implode, scattering glass fragments like a hand grenade. People who repair CRTs and televisions for a living treat them with great respect, and so should you. If you must repair a CRT, take it to someone who knows what they are doing. You have been warned.
Check the obvious things first. Verify that the CRT is plugged in (and that the receptacle has power), the video cable is connected to the video card, the computer and CRT are turned on, and the brightness and contrast settings are set to the middle of their range. If none of these steps solves the problem, your CRT, video card, or video cable may be bad. Check the suspect CRT on a known-good system or a known-good CRT on the problem system.
If you have ACPI or APM power management enabled, it may be causing the problem. Some systems simply refuse to wake up once power management puts them to sleep. We have seen such systems survive a hardware reset without restoring power to the CRT. To verify this problem, turn off power to the system and CRT and then turn them back on. If the CRT then displays an image, check the power management settings in your BIOS and operating system and disable them if necessary.
The horizontal and/or vertical deflection system has failed. The CRT tube itself is fine, but the circuitry driving the tube has failed. Replace the display.
Catastrophic CRT failure is imminent. The noises are caused by high-voltage arcing, and the smell is caused by burning insulation. Unplug the CRT from the wall before it catches fire, literally.
There are two likely causes. First, you may be driving the CRT beyond its design limits. Some CRTs display a usable image at resolutions and/or refresh rates higher than they are designed to use, but under such abuse the expected life of the CRT is shortened dramatically, perhaps to minutes. To correct this problem, change video settings to values that are within the CRT"s design specifications. Second, the power receptacle may be supplying voltage lower than the CRT requires. To correct this problem, connect the CRT to a different circuit or to a UPS or power conditioner that supplies standard voltage regardless of input voltage.
This is usually a minor hardware problem. The most likely cause is that the signal cable is not connected tightly to the CRT and/or video card, causing some pins to make contact intermittently or not at all. Verify that no pins are loose, bent, or missing on the cable or the connectors on the CRT and video card, and then tighten the cable at both ends, If that doesn"t fix the problem, open the computer, remove the video card, and reseat it fully.
In elderly systems, another possible cause is that some hardware DVD decoder cards "steal" one color (usually magenta) and use it to map the DVD video signal onto the standard video signal. Remove the DVD decoder card. If your video adapter includes hardware DVD support, or if you are upgrading to such an adapter, you don"t need a DVD decoder card.
The most likely cause is that the refresh rate is set too low. Change the refresh rate to at least 75 Hz. Flicker also results from interaction with fluorescent lights, which operate on 60 Hz AC and can heterodyne visually with the CRT. This can occur at 60 Hz (which is far too low a refresh rate anyway), but can also occur at 120 Hz. If you"re running at 120 Hz refresh and experience flicker, either use incandescent lighting or reset the refresh rate to something other than 120 Hz.
The video card settings are likely outside the range supported by the CRT, particularly if you have just installed the CRT or have just changed video settings. To verify this, restart the system in Safe Mode (press F8 during boot to display the Windows boot menu and choose Safe Mode). If the system displays a VGA image properly, change your display settings to something supported by the CRT.
Most modern CRTs can display signals at many different scan frequencies, but this doesn"t mean that the CRT will necessarily automatically display different signals full-screen and properly aligned. Use the CRT controls to adjust the size and alignment of the image.
Depending on the CRT, video card, and video settings, this may be normal behavior, adjustable using the CRT controls. If the distortion is beyond the ability of the controls to correct, the problem may be with the video card, the CRT, or the driver. First try changing video settings. If the problem persists at several settings, move that CRT to a different system (or use a different video card) to determine whether the problem is caused by the CRT or video card. Repair or replace the faulty component.
This is usually caused by RF interference from another electrical or electronic device, particularly one that contains a motor. Make sure such devices are at least three feet from the CRT. Note that such interference can sometimes penetrate typical residential and office walls, so if the CRT is close to a wall, check the other side. Such image problems can also be caused by interference carried by the power line or by voltage variations in the AC power supply. To eliminate interference, plug the CRT into a surge protector. Better still, plug it into a UPS or power conditioner that supplies clean power at a constant voltage.
The CRT may need to be degaussed. A CRT that sits in one position for months or years can be affected even by the earth"s very weak magnetic field, causing distortion and other display problems. Exposing a CRT to a strong magnetic field, such as unshielded speakers, can cause more extreme image problems. Many modern CRTs degauss themselves automatically each time you cycle the power, but some have a manual degauss button that you must remember to use. If your CRT has a manual degauss button, use it every month or two. The degaussing circuitry in some CRTs has limited power. We have seen CRTs that were accidentally exposed to strong magnetic fields, resulting in a badly distorted image. Built-in degaussing did little or nothing. In that case, you can sometimes fix the problem by using a separate degaussing coil, available at RadioShack and similar stores for a few dollars. We have, however, seen CRTs that were so badly "magnet burned" that even a standalone degaussing coil could not completely eliminate the problem. The moral is to keep magnets away from your CRT, including those in speakers that are not video-shielded.
An incorrect yoke may have been attached to the CRT. Unless you have a lot of spare time on your hands, this is usually not worth fixing. Replace the display.
If your LCD displays no image at all and you are certain that it is receiving power and video signal, first adjust the brightness and contrast settings to higher values. If that doesn"t work, turn off the system and LCD, disconnect the LCD signal cable from the computer, and turn on the LCD by itself. It should display some sort of initialization screen, if only perhaps a "No video signal" message. If nothing lights up and no message is displayed, contact technical support for your LCD manufacturer. If your LCD supports multiple inputs, you may need to press a button to cycle through the inputs and set it to the correct one.
Unlike CRTs, where increasing the refresh rate always reduces flicker, LCDs have an optimal refresh rate that may be lower than the highest refresh rate supported. For example, a 17" LCD operating in analog mode may support 60 Hz and 75 Hz refresh. Although it sounds counterintuitive to anyone whose experience has been with CRTs, reducing the refresh rate from 75 Hz to 60 Hz may improve image stability. Check the manual to determine the optimum refresh rate for your LCD, and set your video adapter to use that rate.
First, try setting the optimal refresh rate as described above. If that doesn"t solve the problem and you are using an analog interface, there are several possible causes, most of which are due to poor synchronization between the video adapter clock and the display clock, or to phase problems. If your LCD has an auto-adjust, auto-setup, or auto-synchronize option, try using that first. If not, try adjusting the phase and/or clock settings manually until you have a usable image. If you are using an extension or longer than standard video cable, try connecting the standard video cable that was supplied with the display. Long analog video cables exacerbate sync problems. Also, if you are using a KVM switch, particularly a manual model, try instead connecting the LCD directly to the video adapter. Many LCDs are difficult or impossible to synchronize if you use a KVM switch. If you are unable to achieve proper synchronization, try connecting the LCD to a different computer. If you are unable to achieve synchronization on the second computer, the LCD may be defective. Finally, note that some models of video adapter simply don"t function well with some models of LCD.
If the screen is displaying a full, stable image, but that image is of poor quality, first verify that the display is not connected through a KVM switch or using an extension cable. If so, connect the display directly to the video adapter using the standard cable. If that is already the case, adjust the brightness, contrast, and focus controls. If you are unable to get a proper image using these controls, the problem is most likely a clock or phase mismatch, which you can cure by taking the steps described in the preceding item.
The best way to adjust clock and phase is to use auto-adjust first. Check the utility and driver CD that came with the monitor. It may have a wizard or at least the appropriate background screens to use while adjusting phase and clock settings. If not, go to the Windows Start menu and select Shutdown. When the screen goes gray and the Windows Shutdown dialog appears, leave that dialog onscreen, but ignore it. Use the gray screen to adjust clock and phase manually. Any problems with clock and phase and any changes you make to the clock and phase settings are clearly evident on the gray screen.
Always adjust clock first. Clock is usually not a problem if you have used the auto-adjust feature of your monitor, but if you do have clock problems they will be evident as large vertical bars on your screen. Tweak the clock setting until those bars disappear. Then adjust phase. Phase problems are evident as thin black lines running horizontally across the screen. Adjust phase until the lines disappear or are minimized.
Not all analog video cards synchronize perfectly with flat panels. The gray Shutdown screen exaggerates the problem, so don"t worry if very tiny movements are visible after you"ve adjusted clock and phase as well as possible. After you"ve set the clock and phase controls for the best image possible on the gray screen, cancel Shutdown and the image should be optimized.
Your video card is supplying a video signal at a bandwidth that is above or below the ability of your LCD to display. Reset your video parameters to be within the range supported by the LCD. If necessary, temporarily connect a different display or start Windows in Safe Mode and choose standard VGA in order to change video settings.
This occurs when you run an LCD at other than its native resolution. For example, if you have a 19" LCD with native 1280x1024 resolution but have your display adapter set to 1024x768, your LCD attempts to display those 1024x768 pixels at full screen size, which physically corresponds to 1280x1024 pixels. The pixel extrapolation needed to fill the screen with the smaller image results in artifacts such as blocky or poorly rendered text, jaggy lines, and so on. Either set your video adapter to display the native resolution of the LCD, or set your LCD to display the lower-resolution image without stretching the display (a feature sometimes referred to as display expansion), so that pixels are displayed 1:1, which results in the lower resolution using less than the entire screen.
This is a characteristic of LCDs, particularly older and inexpensive models, caused by defective pixels. Manufacturers set a threshold number below which they consider a display acceptable. That number varies with the manufacturer, the model, and the size of the display, but is typically in the range of 5 to 10 pixels. (Better LCDs nowadays usually have zero dead pixels.) Nothing can be done to fix defective pixels. Manufacturers will not replace LCDs under warranty unless the number of defective pixels exceeds the threshold number.
Some people claim that leaving the unit powered off for a day or two will "erase" a persistent after-image. Others suggest leaving a neutral gray screen (like the one used for phase adjustment) up on the screen to "equalize" the display. I dunno. FWIW, I"ve seen this problem on older Samsung panels but never on the Sony or NEC/LaCie panels I use.
Again, this is a characteristic of LCDs, particularly older and inexpensive models. The after-image occurs when the display has had the same image in one place for a long time. The after-image may persist even after you turn the display off.
Transistor-based pixels in an LCD respond more slowly than the phosphors in a CRT. The least-expensive LCDs exhibit this problem even with slow image movement, as when you drag a window. Better LCDs handle moderately fast image movement without ghosting, but exhibit the problem on fast-motion video. The best LCDs handle even fast-motion video and 3D gaming very well. The only solution to this problem is to upgrade to an LCD with faster response time.
Use the brightness control to increase image brightness. If you have set brightness to maximum and the image is still too dim, contact the display manufacturer. The CCRTs used to backlight the screen have a finite lifetime and may begin to dim as they near the end of their life.
If one or more horizontal and/or vertical lines appear on the display, first power-reset the computer and display. If the lines persist, run the auto-setup function of your display. If that does not solve the problem, power the system and display down, remove the video cable, and verify that the video plugs and jacks on both computer and display ends do not have broken or bent pins. Even if all appears correct, try a different video cable. If the problem persists, contact the display manufacturer.
Chemicals leaking from millions of computer screens in homes, offices and schools could damage human health, according to research by Chinese scientists.
Chemistry professor Su Guanyong and colleagues at Nanjing University of Science and Technology in eastern Jiangsu province studied more than 360 types of chemicals used in computer and mobile phone screens and found that 87 of them could be a danger if they got into the environment.
Some chemicals in liquid crystal displays (LCDs) could alter genes, they said. Animal cells mutated unexpectedly if exposed, and preliminary results of their ongoing study published in Proceedings of the National Academy of Sciences on Monday showed that one of the most polluted places was the home.
Researchers said about a quarter of the chemicals from screens they tested might be pollutants. Photo: Getty alt=Researchers said about a quarter of the chemicals from screens they tested might be pollutants. Photo: Getty
Studies found that excessive radiation from screens could speed up the ageing of skin and blue light from diodes could harm the retina of the eye. "But nobody has looked beyond the brightness to unveil the dark secrets behind," Su said.
Over the years, screen panel manufacturers have pushed LCD technology to higher resolutions and faster refreshing rates, but the chemical composition of the liquid crystal that fills their screens has hardly changed.
Su and colleagues produced a list of chemicals used by manufacturers and found that 87 " about a quarter of the substances tested " might be "persisting organic pollutants" that were not only harmful to health, but their composition meant they would take years or sometimes decades to decompose. The exact effect of these chemicals was unknown.
Smartphones mean booming demand for components such as screens. Photo: Ben Sin alt=Smartphones mean booming demand for components such as screens. Photo: Ben Sin
They exposed embryonic chicken cells to liquid crystal taken from the screens and compared them to cells grown in normal conditions. They found genetic changes that suggested the exposed cells had mutated.
The Nanjing team was baffled by the amount of liquid crystal in the air. They knew screens were made in dust-free factories and sealed, but their surveys of hotels, school buildings, canteens, dormitories, electronic product repair centres, homes and laboratories revealed surprising results.
Scientists say cracked screens and leaking chemicals are a worldwide problem. Photo: Shutterstock alt=Scientists say cracked screens and leaking chemicals are a worldwide problem. Photo: Shutterstock
The lowest levels were found in a canteen, a dormitory and classrooms. Su said they were not sure where the drifting liquid crystals came from. Some screens might have been cracked or broken, he said. If a screen was left on for a long time, heat and radiation might cause liquid crystal to evaporate.
There was no solution to the problem at this stage, the researchers said. To push the government for more strict regulations meant that the scientific community had to come up with more evidence and a better understanding of the problem.
"Electric device recycling plants could be a major source of emissions, with broken screens dumped everywhere and little protection. This practice must stop," he said.
This article originally appeared in the South China Morning Post (SCMP), the most authoritative voice reporting on China and Asia for more than a century. For more SCMP stories, please explore the SCMP app or visit the SCMP"s Facebook and Twitter pages. Copyright © 2019 South China Morning Post Publishers Ltd. All rights reserved.
Dell recommends ensuring that the device drivers and BIOS are up to date using the SupportAssist application for optimal video performance and to help resolve common video-related issues.
NOTE: When SupportAssist does not show up in the search results, go to the SupportAssist for PCs and tablets page for information about downloading and installing SupportAssist.
To learn how to manually download and install a device driver such as Chipset, Video card (GPU), and Monitor driver (if required, most monitor drivers are delivered automatically through Windows Update) on your Dell computer, see the Dell knowledge base article How to Download and Install Dell Drivers.
We must verify whether the problem is the display screen of the laptop, video card (GPU), or video settings on the computer. A straightforward way to identify this is to connect the laptop to an external monitor or TV.
If the issue persists on the external monitor, it may be an issue with the video card (GPU) or video settings and not the laptop LCD panel. Go to verify display or video issues in Windows Safe Mode. Otherwise, go to the next step.
Performance issues may occur if there is any damage to the LCD screen. The display may stop working, work intermittently, flicker, display horizontal or vertical lines, and so on, if there is damage to the display screen.
Dell laptops have integrated diagnostic tools that can determine if the screen abnormality is an inherent problem with the LCD screen of the Dell laptop or with the video card (GPU) and computer settings.
When you notice screen abnormalities like flickering, distortion, clarity issues, fuzzy or blurry images, horizontal or vertical lines, color fade, running a diagnostic test on the LCD helps identify if the issue is with the LCD panel.
Press and hold the D key and turn on the computer to enter the LCD built-in self-test (BIST) mode. Continue to hold the D key until you see the entire screen change colors.
If you do not detect any screen abnormalities in the integrated self-test mode, the LCD panel of the laptop is functioning properly. Go to the Update the video card (GPU) driver, monitor driver, and BIOS section.
If you notice any abnormalities in the LCD built-in self-test mode, contact Dell Technical Support to learn more about repair options that are available in your region.
Windows updates can support your Windows operating system in many ways. Windows updates can solve specific problems, provide security patches and protection from malicious attacks, or even add new features to the operating system.
Display settings like brightness, refresh rate, resolution, and power management may affect the performance of the LCD screen on your Dell laptop. Changing or adjusting the display settings can help resolve several types of video issues.
Stress Test can thoroughly diagnose the video card (GPU) on your computer and report any potential hardware problem. Running a stress test on your computer can verify if the hardware components are stable and thus reliable.
System Restore is an integrated Windows tool that is designed to protect and repair the operating system. When something goes wrong with your computer, System Restore must be used before you try to restore the operating system to factory default settings.
If the diagnostic tests on the LCD panel and the video card (GPU) passed, it is most definitely an issue that is related to software that is installed on the computer. If the above troubleshooting steps did not resolve the issue, you may try to restore the computer to factory default settings as a last resort.
The difference between a LED TV and a LCD TV is that they are both LCD TV’s except one has LED stripes and the other has CCFL Backlights- (Florescent Tubes). I used a Philips Magnavox Emerson LG TV when testing these repaird, but they should work on other TV brands that are similar. Before you do any Repair, check to see if you are still under warranty, or are covered by a recall of your TV!!
Unplug the cable between power board and the main board. If the back-light turns on it means that power board is working and the problem is with the main board
If your Plasma or LCD/LED or CCFL/LCD TV or monitor has stopped working, or is displaying one of the following symptoms, then it *may* need some new capacitors in the power supply board or a replacement board
Unplug the cable between power board and the main board. If the back-light turns on it means that power board is working and the problem is with the main board
-Upon three unsuccessful start up attempts the TV locks itself in protection mode and needs to be disconnected from AC for 30-40 seconds before power attempts can be restore-Display Locks after 10 minutes–
1) the front green LED of your TV comes and stays on for 20-30 seconds, then turns off for 1-2 seconds and then keeps cycling like that, but the display never comes;
2) the display comes on for a brief few seconds, then the TV shuts off; in some models the display may not even come on, but still the relay clicking on and off and the green power LED activation and shutdown can be easily observed.
Look at the screen. If you see a blank screen with a red key on the bottom of the screen, press FUNCTION and MUTE at the same time. This will unlock the channel
Choose On to disable all the buttons on the front of the TV. FPA Lock On will appear on the TV screen each time you press buttons on the front of the TV. You can still operate the TV with the remote control. You can still use the POWER button on the front of the TV, but only to turn off the TV (not on). Set FPA Lock to Off to cancel this feature so you can use the buttons on the front of the TV again.
3. Press and hold each of the remaining buttons on the TV, one at a time, for about five seconds, and then release. DO NOT use the buttons on the remote control - only use the buttons on the TV itself.
If the TV still does not display anything, try the menu button on the TV and see if you can access the menu. If not, try using the remote control’s menu button.
If the TV is still locked and will not respond to any commands from the front panel control buttons or the remote control unit, it is apparently locked in a failure or diagnostic mode, and would probably have to be diagnosed and repaired by a reputable TV repair facility. Good luck.
If it is a thin vertical line that appears on certain video resolution/image then it is normal and is indicated in the users manual under troubleshooting. If the line is almost half the screen, it could be a problem with the cable connection between the LCD panel and logic board, or the LCD panel itself. Try reseating the cable first if it’ll solve the problem. I’ve done similar issue in the past. Reseating the cable worked for a couple of months till eventually the LCD panel is the problem. Replacing the LCD panel is quite costly and impractical.
If the lines/bars are across the OSD Menu, and all the video signal inputs also same result, that means the TV LCD Panel is defective Most of the time this symptom is caused by a bad LCD Panel 95%. You can try refitting LVDS Cable or replacing Main Board capacitors or replacing Main Board—5%
Bad news unfortunately, their are two possible causes for what you have described, one would be a fault with the picture drive pcb ( Power Control Board ), and the other is physical damage to the LCD cell matrix, (screen).
There’s videos on how to fix this. It has to do with putting foam, in between panel frame and screen, which applies pressure to solder joints, which then completes the circuit- Contact my10cents, for better explanation.
Big Black Bar on bottom of TV Screen– If the bar that appears in the bottom is showing the energy saving logo, HDMI, Dolby surround and pc mode capabilities look into your remote.
Is the OSD menu affected as well? If yes then possibility could be the LCD Panel or the t-con board. Since you have replaced the t-con board then possibility is the LCD panel. There could be also a possibility of mainboard where upgrading the firmware could restore the picture. If the OSD menu is not affected then the LCD panel is good.
If the lines are across the OSD menu then chances is very high the LCD panel is the cause of the problem otherwise it can be due to bad T-con board or even Mainboard. Have you tested on the OSD menu to see if the lines are really across the menu?
White Lines– There are several possibilities that can cause white lines on an lcd screen. One would be high temperature on the logic board. Logic board drives the LCD panel and when it overheats can cause this display problem. One solution would be to clean the vent holes around the TV. One possibility that I have experienced myself servicing is a bloated capacitor on the power supply board. The worst possibility is a defective LCD panel, which is costly to repair, and sometime more practical to buy a new TV set.
Do you get blue screen when using x-box or DVD, VCR? Have you tried to reset cable box if you have one? Reset TV. Check all cable connections? Try these first.
Do you use the Set top box for cable channels? If yes then try connecting through HDMI and see if you can see the TV. Also do you get blue screen when using x-box or DVD, VCR?
There are several problems that could cause this problem. It could be the connection from the T-Con board to the panel, try wiggling these cables around and see if the picture comes up even for a second. The Mainboard or it’s cables are not the issue in my opinion. The isdsue is either going to be a bad capacitor, faulty output from the power supply to the T-Con board, a bad connection from T-Con to panel, or the T Con or the panel itself are faulty.
Basic things you can do is to check the connections. If you have a cable box, check the video connections. And while doing that, unplug the TV and the cable box from the AC outlet for it to reset. These are the most likely cause of a blue screen
Most of the new TVs display a blue screen when theres no signal for it to lock on. Try unplugging it for about 5-10 minutes and see if that clears up the problem. Why? Because they have microprocessors in em (computer chips) and just as like with any other operating system, they can hang up or crash. This isnt an uncommon problem with todays TV sets. Unplugging it for awhile resets the microprocessor (in other words, it causes it to re-boot when you plug it in again).-
It could be the connection from the T-Con board to the panel, try wiggling these cables around and see if the picture comes up even for a second. The Mainboard or it’s cables are not the issue in my opinion. This is due to either a bad capacitor, faulty output from the power supply to the T-Con board, a bad connection from T-Con to panel, or the T Con or the panel itself are fault. Also, it’s possible the A/V receiver’s Video On feature was turned off by an electrical surge or something else.Turn the Video feature back to On and suddenly that bad blue screen was gone.
Repair/Solution: Change the cable box to a fixed resolution. OR have the customer install the latest TV firmware which can be located at your TV Brand Customer Support
Your power board needs serious help–If you want to repair you have to replace Switching Mosfets, disc capacitors and of course the main fuse, Rectifier Diodes and most of the time the transformer–Costly–Easier to replace Power Board–There is a chance the strike come through the cable line, so it’s possible the Main Board needs repair–That’s a small chance though, but I thought I’d let you know–Replacing power board should repair your TV. During a lightning storm, electrical power surges is induced to the transmission line eventually end to our household appliances. Our TV sets, computers are the most susceptible. For the TV set, the basic cure is to leave the TV unplug from the AC outlet for it to discharge and reset
5. wait another 30 seconds and some type of picture should appear—If that does not work–Unplug TV for 10 minutes and then hold power button on TV for 60 seconds–Plug in and turn on.
Unplug TV– On TV, hold the power button down while pushing and holding each button for a few seconds. After going through all buttons, (on TV) then plug TV back in and it should power up–
Now we need to know if PSU Board has all the correct output voltages. This means checking the secondary side output voltages of Power Board. Probable causes are the Power Supply, the T-Con board, Main Board or the LCD panel itself has failed.
No Picture/Sound The person who looked at my TV, stated that the high voltage power supply needs to be replaced. He explained that I have a low voltage supply which is why the power button is lit once pressed, and a high voltage supply which needs to be replaced.
Solutions: If the unit tries to turn on but begins to cycle on and off before any video is displayed and all of the SMPS (Power Board ) voltages are good, disconnect the LVDS cable at the T-Con board
You will have to go into the TV and check for capacitors or burn marks or cracked solder around the pins–Main board could be IC’s, or regulators–Panel–Disconnect panel and see if your TV stay’s on—
The flashing green light indicates a fault on the power board inside your TV. This will be due to a faulty component like a capacitor or voltage regulator. Faulty electrolytic capacitors on the power board are the most common cause of this problem. These capacitors will often leak and stop working as the TV set gets older,but could also be caused by the Main Board or the inverter board. (LCD TV ONLY) So we will have to take a look inside and maybe do some circuit testing and a visual of your boards-
In a dark room take a flashlight and at an angle shine it on the screen and see if you can see any movement. If you can see movement or see your menu then its backlight failure. If totally black screen with sound then its T-Con board. So if you see movement on a led screen, then it’s your LEDs inside the panel. If on a LCD TV you see movement and lamps are not turning on, replace inverter. If with a LCD TV your lamps turn on, with no picture replace T-Con Board.
Plasma is the most durable in terms of panel failure. LED/LCD is terrible for panel failure. (But every model gets bad apples. Samsung LED/LCD panels die frequently. LG panels are a lot more reliable.) Overall I’d say plasma is more reliable, and even if it fails, in most cases plasma is repairable, LED/LCD is expensive to repair and often difficult to troubleshoot.
3)- Switches off for a second or two intermittently. Relay clicks and standby LED remains green. Switches off intermittently with green LED on, no sound or no picture.
A blurry image on a high-definition LCD TV is typically the result of a mismatch between the TVs resolution capabilities and the resolution of the signal that is coming from connected devices, such as a DVD player or satellite TV receiver. Typically, blurry pictures result when a peripheral device connects to the TV through non HD cables and jacks.
Responsible for performing installations and repairs (motors, starters, fuses, electrical power to machine etc.) for industrial equipment and machines in order to support the achievement of Nelson-Miller’s business goals and objectives:
• Perform highly diversified duties to install and maintain electrical apparatus on production machines and any other facility equipment (Screen Print, Punch Press, Steel Rule Die, Automated Machines, Turret, Laser Cutting Machines, etc.).
• Provide electrical emergency/unscheduled diagnostics, repairs of production equipment during production and performs scheduled electrical maintenance repairs of production equipment during machine service.
Have you ever properly checked the display quality of the LCD you habitually use? Very often people become aware of previously unnoticed problems in display quality when they run a check using test patterns and so on. This time we are going to talk about the basic points used to assess LCD display quality, and show you a simple way to test it.
Below is the translation from the Japanese of the ITmedia article "The difference in image quality is perfectly obvious! – Let"s check the LCD"s monitor" published April 22, 2010. Copyright 2011 ITmedia Inc. All Rights Reserved.
That"s right. The answer is "LCD" (it is displayed if you drag the space between the brackets). We assume that probably many users could read the letters concealed in the squares.
So, the next test is much more difficult. A word is concealed in the four squares below, just as in the image above. The letters are written in colors that are very similar to those of the boxes and we expect that, in many cases, it is hard to distinguish them in your browser. We would like you to download the image and check it closely in photo retouching software or a viewer that is capable of accurate color reproduction.
This time the answer is "EIZO" (it is displayed if you drag the space between the brackets). Depending on the lighting or the user"s environment it may be hard to make out but, if you can read these four letters, the display quality, or more accurately the still image gradation expression, of your LCD is extremely high.
Let"s get down to details then. "Image quality" is the top priority of the LCD, of course. However, recently LCD prices are fiercely competitive and there are surprisingly few products that insist on high image quality and performance. It may be nice to be able to get hold of a wide-screen monitor with full HD (1920 × 1080 dot) resolution or higher fairly cheaply, but it cannot be denied that such LCDs tend not to place too much importance on display quality.
On the other hand, the increasing opportunities to enjoy things like HD videos and games, and high resolution digital photographs on the computer make LCD display quality even more important. As far as possible it"s best to use an LCD with excellent display quality in order to fully enjoy the charms of the visual content.
Even so, perhaps you think that there can"t really be that much wrong with the LCDs that so many people are using at the moment. Here we would like to show you a simple method to check LCD display quality. You can get a good idea of whether the basic display quality is good or bad just by looking at how some simple test images are displayed, just like in the introductory quiz. First of all, we would like you to get a sense of how important it is that "image data can be properly displayed" by checking the display of the LCD that you currently use, (that"s right, the one you are using to view this page!).
The test items use color / monochrome patterned images to check gradation expression, and simple images to check brightness / chromaticity variation. Downloads are available of several test images, such as gradation patterns. We would like you to display the downloaded test images in photo retouching software or a viewer that can reproduce color accurately. As we mentioned at the start of this article, you have to be careful as in many cases colors cannot be displayed accurately in web browsers. (Currently only a few browsers such as Safari and Firefox 3.x can handle color management).
Before starting your visual check of the display quality, please return to your LCD"s setting to default, and select Adobe RGB or sRGB as the image quality mode. If these modes are not available it is fine to set the color temperature to 6500K and gamma to 2.2. If you cannot adjust the color temperature and gamma, simply adjust the brightness and contrast so that they are easier to discern. Of course, if it"s an LCD environment that has been color calibrated it"s OK to leave it as it is.
The average LCD takes some time for the monitor to stabilize after it is switched on so, after start up, please wait at least 30 minutes or so before doing the test. (Most EIZO monitors are an exception to this as they are equipped with our proprietary dimming function and the monitor stabilizes in a short time after start up.)
We would also like you to adjust the monitor stand so that things like the room"s lighting are not reflected on the screen. You have to be particularly careful with products that have a glare (glossy) type screen as they are highly reflective. Visual assessment is impeded when ambient light is reflected. It will be much easier to make an assessment if you turn off the room lights at night and exclude as much ambient light as possible. This applies for both glare and non-glare (matte) types.
The surface treatment of an LCD makes a difference to the background reflection. Glare panels impede the surface diffusion of backlight, which does make it easier to achieve high color purity, but also makes distinct reflections of the user or lighting much more likely (photo on the left).
For your reference, we ran a test on an EIZO 24.1-inch wide-screen LCD, the FlexScan SX2462W, for this article. The FlexScan SX series comes with a number of high image quality functions and boasts top class display quality as a general-purpose LCD intended for a computer.
When we displayed the quiz images (the more difficult ones, of course) on the FlexScan SX2462W, the four letters appeared faintly when we stared closely at the screen and we could read what they said. This indicates the high image quality level.
When checking the display quality of an LCD it is comparatively easy to understand the gradation expression capability by a visual check. Let"s display color and monochrome gradation images and check whether the entire image is smoothly reproduced. If there is a problem with the gradation expression it produces things like blocked-up shadows in dark areas and blown-out highlights in light areas, banding (vertical or horizontal stripes) in the middle gradations, and color cast, so you should check for problems like these.
Test images of color / monochrome gradations are shown below. Each test image is prepared for three resolution levels (1280 × 800 dots / 1680 × 1050 dots / 1920 × 1200 dots). When you click on an image it is displayed in that actual resolution. We would like you to download the images in the resolution which matches that of your current LCD. Gradation expression can vary according to whether the image is viewed horizontally or vertically, so it will be more effective if you rotate these images and view them vertically as well.
A gradation pattern where the colors red, green, blue, cyan, magenta and yellow go through 16 gradients as they change to white or black. This is an easy test image so we expect that it can be seen in most environments that each color bar is divided into 16 blocks.
A gradation pattern where the colors red, green, blue, cyan, magenta and yellow go through 64 gradients as they change to white or black. Each color bar is divided into 64 rectangular blocks. With this many gradients we expect that many LCDs will find it hard to make distinctions in the dark areas or the areas that are close to primary colors.
A smooth gradation pattern where the colors red, green, blue, cyan, magenta and yellow go through 256 gradients as they change to white or black. At this level of difficulty you cannot distinguish between adjoining colors from a distance but, if you have an LCD with excellent gradation expression, if you look closely you should be able to see that each color is divided into thin rectangular blocks.
A gradation pattern that changes from black to white. It is divided into 5 horizontal bars: from the top, smooth, 128 gradients, 64 gradients, 32 gradients and 16 gradients. Even if all the differences can be distinguished in the 16 and 32 gradient patterns near the bottom, we expect that there will be some parts in the 64 and 128 gradient patterns where it is hard to see the boundaries between adjoining colors. With this kind of monochrome test image you should also check whether any unnecessary colors are mixed with the gray.
On an average LCD gradations of gray that are close to black tend to appear as blocked-up shadows (gradations of gray that are close to white are displayed comparatively accurately). If your LCD"s OSD menu allows you to adjust the contrast, please try gradually turning down the contrast. Turning down the contrast often makes it possible to see gradations that had been subject to blocked-up shadows or blown-out highlights.
Probably most LCDs will be able to detect some degree of banding and color cast in the middle gradations. Banding in the middle gradations is tone jump (Missing gradations) and, along with color cast, means that the RGB gamma curves are unequal. Unlike blocked-up shadows or blown-out highlights, this is an area that it is hard to improve with adjustments made by the user.
When we looked at these test images on the FlexScan SX2462W, in the smooth gradation there was blocked-up shadows right next to the black but we could distinguish differences in gradations of gray until very close to the black area. When it comes to such subtle gradation distinctions the brightness of the room and the adaptability of the eye come into play, so the range that is visible will vary according to the environment and the individual. The gradation expression was excellent, with almost no blown-out highlights in light areas, middle gradation banding or color cast.
The FlexScan SX2462W has a 16-bit look-up table (around 278 trillion colors). It converts the 8-bit RGB input from the computer into multiple tones and then reallocates them in 8-bit RGB for their display. (10-bit display is also supported with the DisplayPort input)
This aligns RGB gamma curves for the entire gradation range from dark to light, making it possible to depict subtle gradations and thus eliminating banding and color cast in the middle gradations.
Smooth color and monochrome gradations displayed on the FlexScan SX2462W. This data is of screen displays photographed with a digital camera so some of the gradations may seem to have been destroyed, but they were cleanly represented when checked visually.
We have talked about ways to check gradation expression. We think that it was comparatively easy to understand about blocked-up shadows in dark areas, blown-out highlights in light areas and banding in middle gradations. However, it is hard to distinguish whether a gradation is being cast with unnecessary color so we would like to add a little more about this.
The answer is "The far right" (it is displayed if you drag the space between the brackets). If the other grays looked correct, color may not be being correctly recognized for a variety of reasons, such as the lighting environment or the LCD settings.
For example, when the room is lit with standard household incandescent lights white and gray look reddish, while fluorescent lights can make them greenish (which is why there is some lighting that is made to conform to color evaluations). What is more, white and gray can have a reddish tinge when the monitor has been set to a low color temperature, while a high setting can give them a bluish tinge. Thus it often happens that the gray in visual data does not look like a true gray.
Another big problem is that the human eye (brain) is easily influenced by surrounding colors. Everyone has probably experienced the phenomenon where, when you come from outdoors into a room lit with incandescent lights, the room seems to be bathed in a reddish light at first but, as your eyes gradually get used to it, you lose all awareness of the redness.
The two image patterns below are easy to understand examples of optical illusions. When you look at them you should be able to understand how heavily the human eye is influenced by surrounding colors.
The gray in the center of each square is in fact exactly the same color in each case (600 × 200 dots). However, the grays with a dark surrounding look light and the ones with a light surrounding look dark, don"t they? This is known as "brightness contrast"
The important thing in actual use is that you should not adjust the image quality of your monitor or edit visual material while looking at colors that are being wrongly recognized like this. There are some products where the RGB values of the monitor can be adjusted individually, but this requires caution since fiddling around randomly often leads to irreparable loss of color balance. An effective way to make subtle adjustments to the color detail of image data is to display neutral gray or white image data and use that as a yardstick.
Now let"s assess the gradation expression with some slightly different test images. Below are color patterns with a spread of pale colors in gradations close to the dark range and the light range. They are arranged so that a distinction cannot be made between adjoining colors on an LCD with insufficient gradation expression.
A color pattern where the lightness and hue gradually change. As the lightness of each color decreases (the nearer it approaches to black), the more difficult it becomes to distinguish between adjoining colors.
We expect that you could roughly get the whole picture in the gradation patterns on the previous page, but in the patterns this time some parts that cannot be seen may have appeared in some cases. As we mentioned earlier, LCDs tend to display gradations close to black as a blocked-up shadows, and color patterns that are close to black are particularly hard to distinguish.
Since there are some parts that cannot be seen, the possibility arises subtle skin colors and tones cannot be accurately recognized when doing things like retouching photographs, though the misrecognition will vary according to the user"s eyesight. People who place importance on color reproduction should probably bear this in mind when they think about replacing their LCD or buying an extra one.
Incidentally, when we checked the FlexScan SX2462W with these tests we could distinguish everything in both the close to white and the close to black patterns. As well as no blown-out highlights or blocked-up shadows, we saw no unnatural color casts.
Along with gradation expression, it is easy to visually check brightness variation and chromaticity variation. Brightness variation scatters brightness around the screen and is easy to notice when you use full-screen display for things like drawing up documents or using spreadsheets. Chromaticity variation scatters color around the screen and is not as easily noticed as brightness variation, but it makes graphics-related displays unnatural and causes deterioration in color reproducibility.
Every LCD has some degree of brightness and chromaticity variation, but there are many products where the variations become more obvious when the brightness is lowered. A comparison of the brightness and chromaticity variation of a number of LCDs reveals that there is a fairly large difference between products, so this is a point to bear in mind.
Brightness and chromaticity variation can be checked with standard Windows or Mac OS X functions. All you need to do is to set the desktop background to "Monochrome" and look at the whole screen from a little way away. Your check will be perfect if you change the desktop background to black, white, gray, then 100% red, green, blue, cyan, magenta and yellow, and then any "near-white pale color".
If you actually try this test you may be surprised to find more variation than you expected when gray or a near-white pale color is displayed. Generally speaking, the center of an LCD screen is the brightest and it gradually gets darker towards the edges. This is no problem if there is not a big difference in brightness between the central and peripheral areas, but there are some products where this difference is very striking.
An example of Windows 7 settings. Set the desktop background to "Monochrome" and then click on "Other". Prepare a color on the "Color settings" screen and use it as the background. (The background color cannot be changed in Windows 7 Starter.)
Incidentally, this test is also an effective way to test the LCD for dot defects (normal lighting / unlit room). We would like you to check the black display in a darkened environment, for example by switching off all the room lights at night. Although you probably saw the whole screen as uniformly black in a light environment, very often in a dark environment you can find variations in some parts due to light leaks.
The FlexScan SX2462W got good results again when we tried it with the brightness and chromaticity variation tests. The brightness decreased slightly at the edges of the screen, particularly the lower edge, but overall the display was even and pleasing. It is installed with a "digital uniformity equalizer" that measures brightness and chromaticity throughout the screen and makes corrections so that the entire screen is uniform.
Monochrome full-screen displays on a FlexScan SX2462W. Only the screen display is shown. The bottom right is a near-white pale orange. There are not many LCDs that can display this kind of pale color as uniformly as this
However, the pitfall here is that it simply means that "the screen is visible". The thing is that the viewing angle specifications are permitted to use the term "visible" until the display contrast ratio drops to an extremely low 10:1 or 5:1 when the screen is viewed from an angle (the steeper the angle from which the LCD screen is viewed, the more the contrast generally declines). In other words, they do not take into account the display uniformity of the central and peripheral areas of the screen, or the level of chromatic change, when the screen is viewed from an angle.
The ideal viewing angles is that the brightness and chromaticity is very uniform and there is not much chromatic change, even when the screen is viewed from a slight angle. The viewing angles given in the specifications are not really very helpful, but you can judge the standard of the panel type that the LCD (liquid crystal panel) adopts. IPS liquid crystal panels have the least change in brightness or chromaticity when the screen is viewed from an angle, and they are followed by VA panels. An IPS or VA liquid crystal panel can be said to indicate the superior nature of the product itself, so this is often included in the catalog or specifications. It is probably a good idea to look through the catalogs of various products.
On the other hand, monitors installed with cost-effective TN liquid crystal panels are in fact the most numerous. However, the TN type lags far behind the IPS and VA types in terms of characteristic viewing angle changes in brightness and chromaticity. Simply viewing the screen from a slightly different angle makes the coloration change dramatically, and the screen looks completely different according to whether it is viewed vertically or horizontally. If the vertical and horizontal viewing angles in the specifications are different then it is a TN type. There are quite a few products with a 20-inch wide screen or larger where colors look different in the central and peripheral areas even when the screen is viewed straight on.
The display on an IPS panel. Even when viewed from this angle, the displayed content can of course be distinguished completely and the colors also show up really well
The display on a VA panel. Compared with the IPS panel the screen is a little whitish and the chromaticity has slipped, but it is a satisfactory viewing angle for actual use
The display on a TN panel. There is a very clear difference from the IPS and VA panels. The display throughout the entire screen lacks uniformity and there is a yellow cast
The gradation images and monochrome images from earlier in this article can be used as they are to check the viewing angles. Display an image on the whole screen, look at it straight on and check whether the brightness and colors are uniform at the top and bottom of the screen, and in the center and at both sides. Then gradually shift the angle from which you view the screen and check how the brightness and coloration change. If you do this with photographic data as well as the test images, you should be able to get a better sense of the difference in the display.
When we checked the viewing angles of the FlexScan SX2462W there was absolutely nothing to criticize since, in addition to the use of an IPS panel, it is equipped with many high image quality functions, including the afore-mentioned digital uniformity correction circuit. The brightness and chromaticity throughout the whole screen is very uniform, and the coloration hardly changed at all when the viewing angle was changed.
Naturally, this is very impressive when doing things like photo retouching, but it is also very pleasant at times like when many people are looking at videos or photographs. You can get a perfect understanding of the viewing angles by a visual check of the display so, if possible, we would like you to check this in the store. You will probably be particularly amazed by the difference between IPS / VA types and TN ones.
We explained here about easy ways to check LCD monitor quality. How were the results for your current LCD? We think that many people were probably very bothered by the blocked-up shadows and blown-out highlights when the test images to check gradation were displayed, by the middle gradation banding, and by the variations in brightness and chromaticity when the monochrome images were displayed.
As we mentioned at the beginning, recently the number of LCDs with excellent display quality is on the decline. Although we would not go so far as to say that the display quality of inexpensive products is poor. Of course a high quality LCD is indispensable if you want to enjoy using your computer, properly handle the needs of applications that require color reproducibility, and to fully enjoy all the benefits of rich content.
The EIZO FlexScan LCD series has excellent display quality in those regards, and we have no qualms about recommending them to everyone. The product line-up is diverse but each model is clearly ranked according to the purpose to which it is suited and its screen size, and