Paper Feed Motor Drive Circuit - Epson FX 1170 - B/W Dot-matrix Printer Service Manual

2.3.5 Paper Feed Motor Drive Circuit

The PF motor (a stepping motor) is used to advance the paper. The minimum advance rate is 1/216 inch. The
motor is a 2-2 phase, constant voltage drive motor. CPU ports (P70 to P73) are used to control the PF motor.
Phase data for the PF motor are outputted through these ports. PFA to PF-B are turned on or off within the
When there is an output at A19 of the CPU, a +35 V voltage is supplied to the PFCOM terminal of the PF motor.
Otherwise, a +5 V voltage is supplied through D1 to hold the motor.
CPU
H
r
I
PFAIN B1 c l
C2
C3
C4
R5
Figure 2-28. Paper Feed Motor Drive Circuit
MOTOR
ASSEMBLY, PF
- - - - - - - -
: ' -
1
R49
u
2-28
- - -
' ' - ' - ;
1
1
<PF MOTOR>
4-ph, 48-p PM type pulse motor
(per phase) (at "C)
25
. . .