JUKI SC-920, Engineer'S Manual, Page: 69 / 75

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E302 Fall detection switch failure
(When the safety sw itch
works) • When fall detection switch is input in the
state that the power is turned ON.
• Check whether the machine head is tilted
without turning OFF the power switch (sewing
machine operation is prohibited for safety
sake).
• Check whether the fall detection switch cord
is caught in the sewing machine or the like.
• Check whether the fall detection switch lever
is caught in something.
• C h e c k w h e t h e r t h e c o n t a c t o f t h e t i l t
detection switch lever with the machine table
is inadequate. (The table has a dent or the
mounting location of the bed strut is too far)
E303 Semicircular plate sensor
error • Semicircular plate sensor signal cannot
be detected.
• C h e c k w h e t h e r t h e m a c h i n e h e a d
corresponds with the machine type setting.
• Check whether the motor encoder connector
is disconnected.
E730 Encoder failure • When the motor signal is not properly
inputted.
• Check the motor signal connector (CN30)
for loose connection and disconnection.
• Check whether the motor signal cord has
broken since the cord is caught in the
machine head.
• Check whether the inserting direction of the
motor encoder connector is wrong.
E731 Motor hole sensor failure
E733
Inverse rotation of motor • This error occurs when the motor is run-
ning at 500 sti/min or more in the oppo-
site direction of that of rotation indication
during motor is running.
• Connection of the encoder of main shaft
motor is wrong.
• Connection for the electric power of main
shaft motor is wrong.
E808 Solenoid short circuit • Solenoid power does not become normal
voltage.
• Check whether the machine head cord is
caught in the pulley cover or the like.
E809 Holding motion failure • Solenoid is not changed over to holding
motion.
• Check whether the solenoid is abnormally
heated. (CTL circuit board asm. Circuit is
broken.
E810 Solenoid current
abnormality • Solenoid rare short-circuit. • Solenoid resistance
E811 Abnormal voltage • When voltage higher than guaranteed
one is inputted.
• 200V has been inputted to SC-920 of
100V specifications.
• JUS : 220V is applied to 120V box.
• CE : 400V is applied to 230V box.
• Check whether the applied power voltage is
higher than the rated v (plus) 10% or
more.
• Check whether 100V/200V changeover
connector is improperly set.
In the aforementioned cases, POWER p.c.b is
broken.
• When voltage lower than guaranteed
one is inputted.
• 100V has been inputted to SC-920 of
200V specifications.
• JUS : 120V is applied to 220V box
• Inner circuit is broken by the applied
overvoltage
• Check whether the voltage is lower than the
rated voltage - (minus) 10% or less.
• Check whether 100V/200V changeover
connector is improperly set.
• C h e c k w h e t h e r f u s e o r r e g e n e r a t i v e
resistance is broken.
E906 Operation panel
transmission failure • Disconnection of operation panel cord
• Operation panel has broken.
• C h e c k t h e o p e r a t i o n p a n e l c o n n e c t o r
( C N 3 8 ) f o r l o o s e c o n n e c t i o n a n d
disconnection.
• Check whether the operation panel cord
has broken since the cord is caught in the
machine head.
E924 Motor driver failure • Motor driver has broken.
E942 Faulty EEPROM • Data cannot be written on the EEPROM. • Turn the power OFF.
No. Description of error detected Cause of occurrence expected Items to be checked