Service manual

Troubleshooting
EPSON FX-880/FX-1180 Service Manual
5-3
Motor Drivers
If a motor is not working but its coils seem okay, check the driver. Also, check the driver whenever you
find a defective motor. (When a motor is defective, it sometimes damages the driver.)
PF Motor Driver
To check the PF motor driver (IC11), disconnect the motor cable from CN8 on the main board. Measure
the resistance across the pins as shown below. Any pin from 7 through 17 can be used as the second pin
(these are all tied together to the ground). The meter readings should hold constant, and all readings
should be within 10% of each other.
Table 5-4. PF Motor Driver Resistance Values
Motor Coil Pins to Measure Across Expected Resistance Level
37-17A
67-17
18 7-17B
21 7-17
Constant and all within ±10%
CR Motor Driver
To check the CR motor driver (IC8), make sure the cable connector from the motor is plugged in at CN9
on the main board. Measure the resistance across the pins as shown below. The meter readings should
hold constant, with the high readings within 10% of each other and the low readings within 10% of each
other.
Table 5-5. CR Motor Driver Resistance Values
Pins to Measure Across Expected Resistance Levels
84High
18 15 High
Both readings should be constant
and within ±10% of each other.
1 4 Low
11 15 Low
Both readings should be constant
and within ±10% of each other.