Brother LK3-B430E Mark II Service Manual page 95

Error status Probable causes
1. Cable related to machine motor
#13
is defective
The
machine
does not
operate
during
sewing,
and the
error code
2. Main circuit board is defective
E-20
appears
when fuse F1 on the main
on the
circuit board has blown.
display
window.
3. Main circuit board defective
1. Synchronizer is defective or
#14
machine is not adjusted
Error code
properly when error code E-20
appears
on the
appears on the display window
display
after the machine is started.
window
after the
machine
operates.
2. A malfunction occurs due to
noise or
defective when error code E-21
appears after the machine is
started.
3. Power supply voltage
abnormally lowers when error
code E-90 appears after the
machine is started.
a. Make sure P3 (DC18) connector on the
power supply circuit board and P13 (DC18)
on the main circuit board are plugged in.
b. Make sure P5 (DC300) connector on the
power supply circuit board and P12
(DC300) connector on the main circuit
board are plugged in.
c. Check the connection between P11 (UVW)
connector on the main circuit board and
the terminal block of the machine motor.
Replace the main circuit board with a new
one when fuse F1 has blown.
Separate P12 (DC300) connectors on the main
circuit board, and measure the resistance
between pins 1 and 2 in the connector on the
main circuit board with the same polarity as
shown in the left figure.
(Use of a digital meter is prohibited.)
If the pointer indicates 10KΩ - 30k Ω on the x
1k Ω range, the main circuit board is not
defective.
Red
After measurement, rejoin P12 connectors.
(If the pointer does not, fuses No.2, 3, and 4
Black
may be blown. Examine them.)
a. Make sure that P2 (SYNCHRO) connector
on the main circuit board and the
synchronizer are plugged in.
b. See 10-7. "Checking the input sensor and
DIP switch input" to make sure that the
synchronizer is connected.
If signal is switched on and off, there is no
problem.
c. Turn the pulley by hand to check it can
easily rotate.
d. If error code E-20 appears when the
machine is stopped, see 6-12. "Adjusting
the thread trimming solenoid position" for
adjustment.
a. Make sure that the ground wire is surely
grounded and there is no equipment that
main PROM is
generates strong electrical noise in the
vicinity.
b. If the machine has been remodeled, return
the machine to its original condition before
checking.
c. If the error still occurs after replacement of
PROM, put the original PROM back before
checking.
See #2-5.
If 550VA /machine is not allocated at the
power source, the voltage will drop as soon
as the machine is started, resulting in this
error.
LK3-B430E Mark II
Check/repair/adjust
10. ELECTRIC MECHANISM
Parts to be replaced
Gate power supply
cable
Motor power
supply cable
Motor cable
Main circuit board
Main circuit board
Synchronizer assy
PROM chip
88