Troubleshooting For Displaying - RCA 50LB45RQ Service Manual

4.2 Troubleshooting for Displaying
Note: If the troubleshooting given below can not help you, change the LCD panel for a try. But we strongly suggest you
regard changing the panel as the last step of fixing the display problem.
No display (including white screen, black screen, etc.)
• Check the power board output and main board input ports to make sure whether the TV has been turned on successfully,
because the failure in power on can lead to a no-display problem.
o If it is proved to have been electrified and turn on, check the LVDS cable first.
• Check if both of the two plugs of the flat cable between mainboard and power board have been well inserted into the slots.
Unstable power supply can also cause serious display problem.
• If the display problem only happens in one input mode, that may be caused by wrong version software. Update the new
software. If that can't help, change the main board for a try.
Screen tearing, or there exists moire on screen
• Bad LVDS cable and inappropriate panel driving voltage is still the biggest factor of this problem. So check them first.
e If the cable and voltage are correct, update the software for a try.
o Sometimes the fastening pieces can make unproper pressure to LCD panel, check them out.
• If the screen tearing happens in one or several input sources while the other source can display normally, it can be caused
by bad mainboard most likely. Please change the mainboard for a try.
• Refer to chapter 5 for more details and resolution ways.
Straight darWlight line(s) on screen
• If the bad line is very narrow, it is usually caused by LCD panel malfunction, change the panel for a try.
• If the lines link together and become a bad band, upgrade the software and then check the ports abd circuits of broken-
down output mode(s).
e If the darWlight line ,or band, apprears in all the input modes, please change the LCD panel. But we suggest you check the
panel inlet board(which links the panel and mainboard though LVDS cable) first, because sometimes the liquid crystal
displaying unit is okay, while the inlet board has a transmitting problem, which also will lead to a displaying failure.
• Refer to chapter 5 for more details and resolution ways.
Color cast or interference
• If the cast or interference happens in only one input mode, check the output port(on mainboard) and transmitting network
(arround mainboard) of that mode.
• If the cast or interference happens in all the input modes, please exclude the malfunction according to easy troubleshooting
for No Display. If that can not help, refer to chapter 5 for more details and resolution ways. In addtion, most of this kind of
problems come from the bad mainboards.
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