Paper Feed Motor Drive Circuit - Epson FX-870 Service Manual

Principles of Operation

Paper Feed Motor Drive Circuit

The PF motor, a stepping motor, advances the paper at a
motor is a 2-2 phase, constant-voltage, drive motor. CPU ports (P70 tc P73) are used to control the
PF motor. Phase data for the PF motor is output through these ports. PFA to PFB are turned on
or off within the pPA1476H (ICl), depending on the phase data sent from the CPU.
When there is an output at A19 of the CPU, a +36 V voltage is supplied to the PFCOM terminal
of the PF motor. Otherwise, a +6 V voltage is supplied through Dl to hold the motor.
CPU
6-28
Figure 6-28. Paper Feed Motor Drive Circuit
advance rate of l/216 inch. This
minimum
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