Kyocera FS-1900 - Toner Motor Control Circuit

4-29
FS-1900
Toner motor control circuit
As TMOTON at #15 of gate array (U204) turns to H, Q218 and Q217 turn on, and +24 V reaches
Q217, R265 and the toner motor, finally driving the toner motor.
If the toner motor is overloaded by some reasons, an overcurrent may flow through the toner motor
beyond the predetermined level, turning Q220 on. Q220, when turned on, causes the current from
the +24 V power supply to flow through Q217, Q220, R267, R268, and to the ground. Consequently,
approximately 3.9 V (H) develops at point A, as limited by the combination of R267, R268, and
DZ206. This voltage is used as TNMOC - toner motor error - which is applied to #17 of CPU
(U201). Thus, CPU determines the toner motor error and lets Call service 7001 be indicated.
GND
GND
GND
1
9
2
16
3
Q217
R267
R268
R266
R265
DZ206
1
2
3
Q220
2
3
1
Q218
TMOTON
+24V2
YC203
TMOTDR
GND
TNMOC
TNMOC
TMOTON
17
15
CPU
U204
Engine board
Toner motor control circuit
Toner
motor
Figure 4-3-8 Toner motor control circuit