Sony KDL22EX308, KDL32EX308 manual Protection Shutdown, Troubleshooting, CTV-68

Chapter 3 - Troubleshooting

Protection Shutdown

Critical voltages and circuit operations are monitored by the CPU on the BAL board. If a fault is detected the unit will be forced to shut down by the CPU. The monitored circuit in which the fault occurred will cause the CPU to flash the standby LED in groups of repeating sequences. The number of blinks in these groups identifies which voltage or circuit caused the protection event.

Not all of the available protect codes are used. Models that are LED backlit do not use the 4-blink balancer error as this circuit is found in models that are backlit with fluorescent lamps. The following list contains the protect circuits and diagnostics codes used in the EX700 models. The troubleshooting flowchart in Figure 3-5 provides guidance in locating the possible component causing the shutdown.

2X: A loss of REG12V from the power supply triggers this protect event. The causes range from a failure of the REG12V line, power supply failure, power supply shutdown, or a problem with the detection circuit on the BAL board.

If a failure occurs on the power supply board that causes a loss of the REG12V line, the standby LED will not light when power is applied to the television. After about 10 seconds, the standby LED will light briefly and begin blinking in groups of 2.

3X: The REG 5V and D3.3V source originating on the BAL board is monitored for low-voltage conditions by CPU IC5000. A failure causing a 3X shutdown would require replacement of the BAL board.

5X: A communications error with the timing control circuits has occurred. Since both of these circuits are located on the TCON board, replacement of the board should remedy the problem. In rare cases a loose or defective LVDS cable could be the cause. If the TCON board is not available as a separate part, the entire LCD panel must be replaced.

6X: If the inverter circuits fail to generate high voltage or one or more of the backlight lamps fails to light, the television will shut down and display this diagnostics error.

7X: A digital thermometer IC located on the BAL board provides a temperature reading of the chassis and LCD panel. If the temperature exceeds a pre-determined point the unit will shut down. If this problem occurs immediately at turn-on, the temperature sensing IC has failed and replacement of the BAL board is required. If this occurs after the unit has been running for a while, check for ventilation issues that could cause the unit to run hotter than normal.

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