JUKI LK-1900AN Engineer's Manual page 120

Trouble
7. Error E305
Thread trimmer sensor error
Cause (1)
7-1) Irregular motor revolu- 1-A) There are irregularities in the
tions
1-B) Motor leads are broken.
1-C) The driver circuit is out of
7-2) No sensor signal entry 2-A) The sensor is out of order or
Use of Test Mode
CP-1 or CP-2
2-B) The INT board connector is
2-C) Sensor mounting position is
Cause (2)
mechanism, such as over-
loading, etc.
The motor is out of order.
order.
broken.
disconnected.
inadequate.
Check and corrective measures
Check the presser bar and thread trimmer
mechanisms and look for the section that is
particularly overloaded or whether screws are
loose.
Disconnect CN44 (red) of the MAIN board
and check the motor resistance. [See the
Pulse Motor/Solenoid Circuit Diagram.] Re-
place the motor.
Replace the MAIN board.
Check whether the sensor lamp is turned ON/
OFF when a metallic plate is moved closer
to or separated from the sensor plane. In the
case of no lamp ON/OFF, the sensor is bro-
ken or the connector block is disconnected.
Check the connection of CN66 (red) of the
INT board.
Check and correct the sensor mounting posi-
tion.