Canon PC980 Service Manual - Page 42

CHAPTER 2 BASIC OPERATION 2. Operations The main motor (M1) is a DC motor with a built-in clock pulse generator, which generates clock pulses (MMCLK) in relation to the rotation of the motor while the motor is rotating. The speed control circuit controls the main motor (M1) so that it rotates at a specific speed by matching the frequency of these clock pulses and that of the reference signals. When the main motor drive signal (MMD) from the DC controller circuit goes '1', the motor diver drive circuit turns on, causing the main motor (M1) to rotate at a specific speed. While the main motor is rotating at a specific speed, the main motor driver PCB keeps sending the constant speed state signal (MLOCK=0) to the DC controller PCB. If the rotation of the motor starts to have fluctuations, the MLOCK signal goes '1'. Related Error Code E010 While the main motor drive signal is generated, the rotation of the main motor deviates from a specific number for 1 sec or more. a. Turning On/Off the Main Motor When the main motor drive signal (MMD) from the DC controller circuit goes '1', the main motor driver turns on to rotate the main motor (M1). b. Rotating the Main Motor at a Constant Speed The drive circuit on the motor driver PCB controls the main motor so that the phase of the frequency of the clock pulse signals (MMCLK) occurring when the motor rotates and that of the frequency of the reference signals match. The main motor driver PCB sends the constant speed state signal (MLOCK=0) to the DC controller circuit. c. Detecting an Error (E010) If the rotation of the main motor starts to have fluctuations for some reason, the MLOCK signal goes '1'. If the signal remains '1' for about 1 sec, the DC controller will find the condition to be a fault in the main motor, and will stop the main motor and, at the same time, indicate 'E010' in the display. 2-6 COPYRIGHT © 1999 CANON INC. CANON PC800s/900s REV.0 AUG. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)