Th-42Xvs30 Tuner Sos Detect - Panasonic GP6DU Technical Manual

TH-42XVS30 Tuner SOS Detect

The SOS detect line from the tuner receiver comes into the TV through the tuner
cable connected to the tuner-in connector on the DR board.
If there is short circuit on this line, Q8200 goes out of conduction providing a high
on pin 10 of the expander I/O IC (IC3004) on the J board.
This change of voltage on pin 10 is reported to the main microprocessor IC
(IC9003) on the D board through the SCL3 and the SDA3 bus line.
The DC level shifter circuit, (Q9000 and Q9002) reduces the signal DC level to
3.3V to match the DC operational level of IC9003.
Figure 43 - Tuner SOS Detect
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