Ricoh FT7770 Service Manual page 579

Service Call 24 -
o After the CPU sends the lower tray up signal or the lower tray
down signal, the CPU does not receive any signal from the
lower tray paper volume sensor within 3 seconds.
Turn the main switch on.
Does the lower tray motor rotate?
N
I
o Turn the main switch off.
o Disconnect connector CN314 from the ac drive unit.
Is the resistance between CN313-4 or CN313-5 and CN313-8
on the ac drive board less than 10 ohm?
N
I
Is the voltage between the trigger signal (CN212-4 or
CN212-5) and TP301 (main motor control board) 0 volt?
Y
Replace the ac drive unit.
Replace the lower tray motor.
Check the signal level of all lower tray sensors.
Lower Tray
N
I
Is the voltage between the trigger signal (CN301
-B17 or CN301-B18) and TP215 (main board) 0 volt?
Y
N
I
Is the voltage between CN302-B17 or CN302-
B18 and TP215 on the dc drive board +3 V?
Replace the main board.
Replace the dc drive board.
Check and correct the harness and connector.
13-55
30
April, '89