March 2000 © TOSHIBA TEC
7-45
DP120F/DP125F Circuit Description
3.12 Fan Motor Drive Circuit
The fan motor drive circuit consists of the I/OP2-GA (IC48), PTC GA (IC45), A/D converter
(IC54) and other peripheral devices. It drives the DC motor connected to CN9 on the Mother
PBA to operate the fan for cooling this machine.
The fan motor is driven by the FANL signal and FANH signal which are output from the I/OP-2
GA. When the FANL signal goes HIGH, Q255 and Q251 turn on and the voltage of the FANPS
signal b18V, thus allowing the fan motor to operate at low speed. When the FANH
signal goes HIGH, Q254 and Q10 turn on and the voltage of the FANPS b24V, thus
allowing the fan motor to operate at high speed. When both FANL and FANH signals go LOW,
the fan motor will be stopped.
A speed of the fan motor is selected according to the fuser’s temperature sensed by the ther-
mistor. The motor stops when the temperature is less than 106°C and operates when 122°C or
more. The speed is also controlled from low to high speed when starting the polygon motor in
the LSU, and from high to low speed when ending the printing.
The connection status of the fan motor is detected by converting the voltage of the FANDET
signal to a digital value by the A/D converter and comparing it with the reference value by the
PTC GA. The digital value distinguishes between connection and non-connection of the fan
motor.
Fig. 7-3-12
07-03-12
Signal Name
Type
Active
Description
Destination
FANL
O
H
Fan Motor Low Speed Signal
Q255
FANH
O
H
Fan Motor High Speed Signal
Q254
FANPS
O
-
Fan Motor Drive Signal
Fan motor
FANDET
I
-
Fan Motor Connection Detect Signal
A/D converter
Summary of Contents for DP120F
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Page 401: ...DP120F DP125F Circuit Description 7 92 March 2000 TOSHIBA TEC 07 05 00 Fig 7 5 1 ...
Page 656: ...DP120F DP125F Troubleshooting 11 44 March 2000 TOSHIBA TEC ...
Page 700: ...DP120F DP125F Appendix 12 2 March 2000 TOSHIBA TEC 1 2 Error Count List ...
Page 701: ...March 2000 TOSHIBA TEC 12 3 DP120F DP125F Appendix 1 3 Function List for Maintenance ...
Page 702: ...DP120F DP125F Appendix 12 4 March 2000 TOSHIBA TEC 1 4 Drum Unit ...
Page 703: ...March 2000 TOSHIBA TEC 12 5 DP120F DP125F Appendix 1 5 Memory Dump List ...
Page 706: ...SHUWA SHIBA PARK BLDG A 2 4 1 SHIBA KOEN MINATO KU TOKYO 105 8524 JAPAN ...