Ricoh FT7770 Service Manual page 576

30 April, '89
Service Call 15 - Lens Drive
o If the CPU does not receive 1 pulse from the lens safety sensor for a 1%
change in the reproduction ratio (lens motor rotates 180 degrees), the CPU
returns the lens unit to the lens home position (1OO% position).
While the lens unit is heading for the home position, if the CPU does not
receive 1 pulse for 6 seconds, SC 15 turns on.
Turn the main switch on.
Does the lens motor move?
Y N
I
Does the lens/mirror motor start signal (CN102-4) go from
zero to 5 volts?
Y N
I
Replace the operation panel board.
Replace the lens/mirror motor control board. If the motor
still does not move, replace the motor.
o Remove the upper front cover.
o Manually move the lens motor.
Does the voltage between CN646-2 and CN646-3 change between 15
volts and 0 volt.
Y N
I
Replace the lens
Does CN101-A16 change
through the home position?
o Replace the lens home position sensor.
o Replace the operation panel.
safety sensor.
from zero to 15 volts as the lens moves
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