4.4.16. Fan Control Circuit
FANCTL:
1. Full Power Mode
When FANCTL signal ( pin 6, IC11 ) is high, pin 7 of IC9 goes high, transistors Q15 and Q17 are turned on. This supplies +24V
Power to Fan motor and rotates the Fan.
2. Reducing Power Mode ( Quiet Mode )
Pulse signal ( see below ) is output from pin 6 of IC11.
This pulse signal is integrated by R177, C181 and C175. Voltage of ( A ) is stabilized at approx. 2V. Pin 6 of IC9 is 0V.
When the voltage of ( B ) is lower than the voltage of ( A ), pin 7 of IC9 goes high, Q15 and Q17 are turned on, then the voltage
of ( B ) increases. When the voltage of ( B ) is higher than ( A ), pin 7 of IC9 goes low, Q15 and Q17 are turned off,then voltage
of ( B ) decreases. Thus the voltage of ( B ) is controlled almost same as the voltage of ( A ) ( = approx. 2V ). Since the resistor
network of R180 and R181 divide the voltage of ( C ) into 1/8, the voltage of ( C )is controlled approx. 16V ( = 2V x 8 ).
FAN Control Mode
Mode FAN Power
Warm Up Full
Printing Full
Others Reduced
FANERR:
This signal is used for detecting whether the rotation of fan motor is proper or not. When the fan motor is not rotating properly or
is locked, this signal becomes a high and inputted into pin18 of IC11.
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KX-P7100