Ricoh FT7770 Service Manual page 578

30 '89
April,
Service Call 23 -
o After the CPU sends the upper tray up signal or the upper tray
down signal, the CPU does not receive any signal from the
upper tray paper volume sensor within 3 seconds.
When the main switch is turned on does the
rotate?
N
Y
I
o Turn the main switch off.
o Disconnect connector CN314 from the
Is the resistance between CN313-2 and
and CN313-8 on the ac drive board less than 10 ohm?
I
Is the voltage between the trigger signal (CN212-2 or
CN212-3) and TP301 (main motor control board) 0 volt?
Replace the ac drive unit.
Replace the upper tray motor.
Check the signal level of all upper tray sensors.
Upper Tray
N
I
Is the voltage between
-A17 or CN301-A18) and
Y N
I
Is the voltage between CN302-A17 or CN302-
A18 and TP215 on the dc drive board +3
volts?
Y N
I
Replace the main board.
Replace the dc drive board.
Check and correct the harness and
the trigger signal (CN301
TP215 (main board) 0 volt?
13-54
upper tray motor
ac drive unit.
CN313-8 or CN313-3
connector.