Panasonic PT-50DL54 Technical Manual page 43

Shutdown - Power LED Blinks 3X Shutdown - Power LED Blinks 3X
If If the power LED blinks 3X and repeats, the problem is caused by non-detected fan the power LED blinks 3X and repeats, the problem is caused by non-detected fan
rotation. Refer to figure 33. Inside each modern fan is a Hall effect circuit that monitor rotation. Refer to figure 33. Inside each modern fan is a Hall effect circuit that monitor
the magnetic field created when the fan rotates. The circuit grounds pin 3 of the the magnetic field created when the fan rotates. The circuit grounds pin 3 of the
respective fan plug to keep the microprocessor from shutting down the TV. respective fan plug to keep the microprocessor from shutting down the TV.
Unpluging the fan plug normally shuts the TV off. When a fan is unplugged, pin 3 rises Unpluging the fan plug normally shuts the TV off. When a fan is unplugged, pin 3 rises
to 4V because of a local PS board pull up resistor. (e.g. R967, R968, or R971). This to 4V because of a local PS board pull up resistor. (e.g. R967, R968, or R971). This
High is applied to Microprocessor IC1103/pin 94 to shutdown the TV. High is applied to Microprocessor IC1103/pin 94 to shutdown the TV.
All the fans are powered by IC953 on All the fans are powered by IC953 on
8-12Vdc. IC953 is controlled by the microprocessor which gets its signal from a 8-12Vdc. IC953 is controlled by the microprocessor which gets its signal from a
temperature sensing IC6904 located in the color wheel assembly (not shown). temperature sensing IC6904 located in the color wheel assembly (not shown).
Troubleshooting tips: Troubleshooting tips:
When the power LED blinks 3X and one of the blades is not turning slower, measure When the power LED blinks 3X and one of the blades is not turning slower, measure
the voltage at pin 3 of all 3 fan plugs. One is likely to have voltage insead of being at the voltage at pin 3 of all 3 fan plugs. One is likely to have voltage insead of being at
zero volts. That fan is defective. If all the voltages are correct at zero volts, and the zero volts. That fan is defective. If all the voltages are correct at zero volts, and the
voltage at DG2/pin 4 = 0Vdc, change the DG board. voltage at DG2/pin 4 = 0Vdc, change the DG board.
the PS board. The fan drive voltage varies from the PS board. The fan drive voltage varies from
Figure 33 - Power LED blinks 3X
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