Service manual

Principles of Operation
Carriage motor drive circuit
The LQ-200/AP3000 includes an STK-6981B, a hybrid integrated circuit used to
drive stepper motors. The STK-6981B (ICSC) circuit drives the stepper motor
under a constant current.
An external voltage level determines the value of the
current. STK-6981B operation is divided into equivalent phases AB and CD. This
section describes phase CD. Figure 2-32 shows the carriage motor drive circuit.
Figure 2-33 shows the STK-6981B circuit diagram.
Figure 2-32.
Carriage Motor Drive Circuit
LQ2OO/AP3000
2-33