PROBLEM/SYMPTOM:

Due to availability, the DTT motor can be substituted for the STT motor.

After replacing a single tach carriage motor with a dual tach carriage motor, the print out in 10 cpi leaves blank columns between the heads. The printer is printing 10 cpi using the 12 cpi tach wheel.

The Single Track Tach (STT) carriage drive motor can be replaced with a Dual Track Tach (DTT) carriage drive motor.

The (STT) motor has a small tachometer board attached to the case. This PCB has adjustments for TACH1 & TACH2 shaping.

The (DTT) motor does not have a tachometer board attached and requires no tach adjustment.

SOLUTION/PROCEDURE:

The tach signal on pin 13 needs to be tied to ground when a DTT motor is used in place of an STT motor. Move the wire on pin 13 (green wire) on the tach connector (J4) to pin 11. Reference Figure 1.