PIONEER CX893
Service Manual

CX-893

1.4 Mechanical control
1) Loading
The microprocessor instructs the motor driver IC651 to rotate backward (IC651: 3 pin: L, 4 pin:Ht¨L+: L, L-:H) if LOAD STRAT SW (SW652) detects OFF (LOAD STRAT=H). If LOAD STRAT SW (SW652) detects ON (LOAD END=L) later, the microprocessor instructs the motor driver IC651 to stop (IC651: 3pin: H, 4pin:Ht¨L+: L, L-:H) and completes the loading and then transits to PLAY operation. If DISC IN SW (SW903) is OFF (DISC IN=H) or LOAD END SW has been OFF for a long time, the microprocessor determines that there is no inserted disc or a disc insertion error and performs EJECT or Error STOP.

2) EJECT
The microprocessor instructs the motor driver IC651 to positively rotate (IC651: 3 pin: H, 4 pin:Lt¨L+: H, L-:L) when it receives the EJECT instruction. If EJECT END SW (SW653) detects ON (EJECT END=L) later, the microprocessor instructs the motor driver IC651 to stop (IC651: 3pin: H, 4pin:Ht¨L+: H, L-:H) and completes the EJECT operation.

1.5 Others
1) Temperature detection
This module detects high temperatures, to protect PU. When the temperature of the output from the temperature sensor (IC402) exceeds a certain voltage level, it is determined as high temperature and an appropriate process such as Error STOP will be performed. The ambient temperature which causes that high temperature on the module is approximately 80 degree Celsius.

2) Voltage monitoring
This module monitors voltage to protect the system. The signals which are resistive divided (R803, 804) from the input VD from the product (CN301: 1,2) are monitored (IC401, 25 pin). If the voltage of the signal is higher than 2.86 V (VD7V or higher) or lower than 2.04 V (VD5V or lower), an appropriate process such as Error STOP will be performed.

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