Ricoh FT7770 Service Manual page 63

Charge Power Pack
4.
The circuit operation for the charge corona begins with the input of +24
volts to the power pack at CN232-6. This voltage powers the LEDs.
Additionally, +24V
supply is used for the high voltage coronas.
The charge corona turns on when the Start key is pressed. The CPU
plies a LOW signal at CN208-B8, this turns on the LED and the phototransis-
tor energizes the power pack.
The charge corona turns on at the same time as the main motor and it turns
off 100 milliseconds before the main motor.
If a charge corona high-voltage leak develops, the charge power pack ac-
tivates PC3. CN201-A6 then becomes LOW. Upon receiving the LOW input,
the CPU lights the Call Service Representative Indicator and displays SC
14.
enters the power pack at CN232-7.
(VP)
2-7
30
April, '89
This power
sup-