Panasonic TH-65PX600U Service Manual page 47

1. The MPU (IC1103) of the DG board monitors the MAIN3.3V, SUB5V and SUB9V
sources of the PA. If any of these voltages is missing, IC1103 shuts down the unit and
the power LED blinks 10 times.
2. The FAN SOS detection input monitors for irregularities in the fan drive circuit. A
broken fan or excessive voltage output of the fan regulator circuit causes the power LED
to blink 11 times.
3. The SOUND SOS detection input monitors for irregularities in the sound output circuit
of the PA board. A defective speaker or excessive current drain of the audio power
amplifier IC causes the power LED to blink 12 times.
4. The POWER SOS detection input monitors for irregularities in the voltage outputs of
the PA board. Excessive voltage output or excessive current drain causes the power
LED to blink 10 times.
5. Since the D board does not control the blinking pattern of the power LED, any SOS
condition detected by IC1103 must be reported to the DG board MPU. The PANEL_
SOS input receives a report of any SOS detection of the D board MPU. The PANEL
STATUS pin of IC1103 is an acknowledgement line that reports to the DG board MPU
the operational status of the D board.
DG Board SOS Detect
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