Canon D78-5382, Service Manual

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1.4 Lens Motor Problems
Check following steps.
Part 4: Troubleshooting
4-6
Logic Table of IC5501/IC5551
Input Output Operation
4 5 7 1
H L L H Forward drive
L H H L Reverse drive
H H L L Braking
L L - - Stand by
Check the power supply (7VMCI) circuit, IC5501 and IC5551 and
peripheral circuit. Check Key SW board.
Both of ZOOM and
FOCUS motors are
not functioning.
No
Yes
Check the ZOOM motor control circuit.
Zoom motor is controlled by signal ZOOM +, - output from
pins 1 and 7 of IC5501. These control signals are driven
by IC301, system control IC, and applied to pins 4 and 5
of IC5501 through the IC1804, I/O-sw IC.
Only ZOOM motor is
not functioning.
No
Yes
Check the FOCUS motor control circuit.
Focus motor is controlled by signal FOCUS +, - output
from pins 1 and 7 of IC5551. These control signals are
driven by IC301, system control IC, and applied to pins 4
and 5 of IC5551 through the IC7801, D/A IC.
Only FOCUS motor is
not functioning.
No
Yes
Check logic table of motor
drive ICs, IC5501, IC5551.