Cleaning Solenoid Circuit - Ricoh FT7770 Service Manual

5. Cleaning Solenoid Circuit

The CPU energizes the cleaning
solenoid one second after the
main switch is turned on. For ini-
tial pressure application, the sole-
noid is energized by +40 volts.
To accomplish this, the CPU
sends +3-volt signals to the dc
drive board from CN206-A4 and
CN202-A13. The dc drive board
then energizes RA701 by supply-
ing a LOW signal at CN301-A20
and Sol-1 by supplying a LOW sig-
nal at CN304-B12.
the +40-volt contacts of RA701
and opens the +24-volt contacts.
The relay stays energized for one
second. After that, the relay
returns to its normal condition
(+40 volts open, +24 volts closed).
This switching happens so quickly
that the cleaning blade mechanism
is not affected.
This closes
2-55
30 April, '89