Ricoh FT7770 Service Manual page 571

Service Call 9 -
o When the Start key is pressed, the CPU does not receive the
encode signal within 200 milliseconds.
When the Start key is pressed and the scanner reaches the
o
home position, the encode pulse count is not within
specifications.
o After the Start key is pressed and the scanner motor has
turned on, the CPU does not receive the encode pulse before
the scanner home position sensor turns on.
o Turn the main switch off.
o Remove the exposure glass.
o Move the scanner to the center manually.
o Turn the main switch on.
Does the scanner motor move?
Y N
I
Is the voltage between CN503-2 and TP507 (GND) on the
scanner motor control board 10 to 15 volts ac?
Y N
I
Does CN501-A6/CN208-B16 go from 15 volts to ground?
Y
Replace the main
Replace the scanner motor.
While manually moving the scanner forward, does the output of
CN505-3 drop from 5 volts to ground and does CN505-4 rise from
ground to 3 volts?
Replace the scanner motor.
Replace the scanner motor control board.
Scanner Motor Encoder
N
I
Replace the scanner motor
board.
control board.
13-47
30 April, '89