Electrical Components - JUKI LK-1900AN Engineer's Manual

(3) Electrical components

Trouble
1. No display at the operation panel.
(Refer to "Block diagram A".)
Cause (1)
1-1) DC power is not sup-
plied.
1-2) Detection of a mo-
mentary interruption in
the SDC board.
LED3 on SDC board:
Flashing 9 times
1-3) Difference in source
voltage
Cause (2)
1-A) AC power is not supplied.
1-B) The FLT board has no power
supply.
1-C) The SDC board has no power
supply.
1-D) The MAIN board has no
power supply.
1-E) The operation panel has no
power supply.
2-A) There is no connection be-
tween CN3 of the FLT board
and CN13 of the SDC board.
2-B) No AC voltage is available
between Pins 4-5 of CN1 in
the FLT board.
3-A) High input voltage
Check and corrective measures
Examine if a power supply is available at the
power switch.
Check whether an AC voltage is available
between Pins 4-5 of CN1 in the FLT board.
If no voltage is found, check the connections
around the power switch.
Check whether DC 280V is available be-
tween Pins 1-3 of CN17 in the SDC board. If
no voltage is found, check the connections
toward the FLT board. If there is no problem
in connections, replace the FLT board.
Check whether DC 5V is available between
Pins 4-8 of CN31 in the MAIN board. Check
the power supply for the SDC board unit and
examine if there is short-circuiting in the 5V
power system.
Confirm that the cable from the operation
panel is connected to CN34 of the MAIN
board. If there is no problem in connections,
replace the MAIN or PANEL board.
Check the connection between CN3 of the
FLT board and CN13 of the SDC board.
When a sewing machine for 3-phase speci-
fications is used in a 1-phase system, con-
nect the power supply to red and white of the
power cord led from the box.
Check the 100/200V selector cord in the FLT
board.
Check the source voltage.