Epson FX-870 Service Manual page 55

Troubleshooting
Sensor
Connector
Number
Release Lever Place one lead on each pin. Change the release
lever position.
(CN4)
Platen Gap Place one lead on each pin. Change the adjust
lever position.
CR Home Place one lead on each pin. Move carriage to and
away from home position.
(CN7)
Front PE Place one lead on each pin. Toggle sensor by
inserting and removing paper.
(CN3)
Sensor
Connector
Number
Rear PE Place one lead on pin 3 (GND) and one on pin 2
(PER). Toggle by inserting and removing paper.
Note: Illustrations later in this chapter show sensor locations.
Table 3-3. Motor Test Points and Coil Resistance
Motor Common
Connector Pin
Number Numbers
Carriage 5
Motor
(CN13)
Paper Feed 6
Motor
5
Common pins may be reversed. If you do not obtain the proper reading with one common, try
Notes:
l
the other common for that motor. If you still do not obtain proper readings, the motor is bad.
If any phase of the motor is shorted, see Table 3-6 to check the main board. (If the drivers on
l
the main board are also shorted, and the board is not replaced at the same time as the motor,
the short in the main board drivers may burn out the new motor.)
3-2
Table 3-2. Sensor Test Points
Test Method
(Set Meter to Ohms.
Check with Printer Power Off.)
Test Method
(Set Meter to Volts.
Check with Printer Power On.)
(Set Meter to Ohms. Disconnect
Test Pin Motor from Main Board and Check
Numbers
it with Printer Power Off.)
Place one lead on pin 5 and the other lead
on each of the four test pins to check the
four motor phases.
1 and2
Put one lead on pin 6 and the other lead
on pin 1 and then on pin 2.
Put one lead on pin 5 and the other lead
on pin 3 and then on pin 4.
Meter Reading
Meter should toggle between
open and short.
Meter should toggle between
open and short.
Meter should toggle between
open and short. (Closed = active.)
Meter should toggle between
open and short. (Open = active.)
Meter Reading
Meter should toggle between 0 V
and HIGH.
Test Method
Meter Reading
(at 77" F,
25" C)
(at 77" F,
25" C)
E p s o n FX-670/1170