Panasonic UF-890 Service Manual page 237

6.2.7 Transmit Motor Control Circuit
The transmit motor is a stepper motor powered by +24 VDC and driven by a 1/2-phase excitation, greater
step division is provided by controlling the phase circuit in steps.
The stepping signal and chopping current control signals (pTINA, pTTDA, pTINB and pTTDB) are sent to
the chopper drive circuit, comprised of IC190 and its peripheral circuitry, from the IC150 (S-CPU) output
port.
S-CPU
IC150
Tx Motor Driver Circuit Block Diagram
Motor Control Signal
(pTINA, pTTDA, pTINB and pTTDB)
+5V
Q193
Q194
+5V
Motor
Driver
IC190
MGND MGND
237
+24V
F190
Transmit Motor