Chapter 3 - Troubleshooting
Backlight Issues
Under normal circumstances, any failures in the backlighting system will cause the unit to shut down. If one or more of the fluorescent backlights fails to turn on, or if the high voltage inverter circuit fails to turn on, the unit will shut down and the standby LED will blink in groups of 6.
The first step to determine the cause of the failure is to observe the screen of the television when it is first turned on. If the backlights turn on before the shutdown, it is likely that one of the lamps has failed to turn on and the LCD panel must be replaced.
If the backlights do not turn on, the high voltage inverter did not start and, depending on the method of generating high voltage, replacement of the power supply or inverter board is necessary.
No Backlight, No Shutdown
It is possible for a symptom of no backlighting to occur that does not cause the television to go into protective shutdown. Dynamic dimming control of the backlights is performed by monitoring information from the TCON board. This is in the form of data and determines the brightness level of the backlights based on video content.
If the TCON fails to process the RGB video data, or if the dimmer data line fails, the backlights will not turn on. Audio will be present if the selected input has it available. The television will remain on indefinitely with the green Power LED lit. If the TCON is available, it can be replaced to resolve the issue. If not, the LCD panel must be replaced.
Diagnostics History
Figure
This feature is useful for failures which are intermittent or when the customer is not sure what is causing the television to shut down sometimes. Once a corrective action is determined the error events should be cleared to zero. This is accomplished by pressing the “8” key followed by the “0” key on the remote commander.
EVENT COUNT
NOT USED
NOT USED
NOT USED
NOT USED
ERROR BLINK COUNT
OPERATING
HOURS
FIGURE
DIAGNOSTICS HISTORY PAGE
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