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Standby & Power-on Circuit
Standby Circuit
Refer to figure 8. When the PT-xxDL54 TV is plugged into an AC outlet, Standby 7Vdc
is output to the P (power supply) board at P5/pin 9. Within the P board, a small 60 Hz
transformer (T802) and a bridge rectifier (D882) is used to produce the standby voltage.
The P board's standby voltage is sent to the DG board (DG2/pin 9) where the standby
7Vdc is regulated to 5V. This standby 5V is applied to Microprocessor IC1103.
Figure 8 - Standby & Power-on Block Diagram
Power-on Circuit
Refer to figure 8. Once standby voltage is available at microprocessor IC1103, it
responds to a power-on command either from the remote (via IR receiver) or from the
front panel power button (both not shown). At power-on, the DG board
microprocessor's "AC_SW" output produces a high (5V) measured at DG2/pin 5. This
High passes through DG2/pin 5, P4/pin 4, and the thermal breaker mounted above the
lamp compartment. This voltage then passes through the lamp door switch before
returning to the P board at P4/pin 1.
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