Brother PC8200 SUPER GALAXIE 2000 Service Manual page 49

* You must turn off the power and remove connectors from printed circuit boards before measuring resistance.
PROBLEM
1. When power is turned
on, buzzer does not
sound and nothing
appears on display.
2. After the power is
turned on, pulse motors
do not return to their
home positions with
respect to the needle
position. (Zigzag pulse
motor when needle bar
is raised and feed and
horizontal feed pulse
motors when needle
bar is lowered.)
3. Pattern cannot be
selected.
4. Main motor does not
run.
CHECK
1) Has the display contrast been adjusted?
2) If the voltage between both inlet terminals is
measured when the power cord is plugged in, is the
standard voltage (120 VAC, 220V, 230V, 240V)
displayed?
3) When power switch is set to on, is resistance between
both ends less than 1 W?
4) Remove connector CN13 from the power supply
board, and check following voltages using a tester:
Voltage between pins 4 and 5 should be 8 to 12 VDC.
Voltage between pins 6 and 7 should be 22 to 26 VDC.
5) Is fuse blown?
6) Others
1) Are the resistances between the connector pins given
below normal for the pulse motors which do not return
to the home position?
(CN13)...... 1-3, 2-3, 4-5, 4-6 ® 8-10 W
Zigzag
(CN16)...... 1-3, 2-3, 4-5, 4-6 ® 8-10 W
Feed
Horizontal (CN17)...... 1-6, 2-5, 3-6, 4-5 ® 8-10 W
2) Set the home position for the same pulse motors
irrespective of needle position.
3) Is a fuse blown?
4) Is the voltage between pins 4-5 normal when the
output connector (CN7) is disconnected from the main
power board ?
Between 4-5 22-26 VDC
5) Others
1) Does switch on SS (VR) PC board remain pressed?
2) When the foot controller is connected, does it remain
depressed?
3) Others
1) Does balance wheel rotate easily?
2) Is main motor connector (CN2 on power supply unit)
attached properly?
3) Is resistance of both ends on main motor connector
(CN2 on power supply unit) 24 to 34 W?
4) Do start/stop switch, needle position switch, and
thread cutter switch operate correctly?
Voltage between ends of each switch should be;
under 1 W when switch is pressed.
infinite when switch is released.
5) Is presser foot lifter lowered? Does presser foot switch
operate correctly?
When presser foot lifter is raised, voltage between
pins 2-1 of fabric thickness detector (CN14) is
approx. 1.5 VDC.
When presser foot lifter is lowered, it is approx. 4
VDC.
6) Others
-47-
REMEDY
1) Adjust the contrast.
2) Replace the power cord.
3) Replace power supply unit
assembly.
4) Replace power supply unit
assembly.
5) Replace fuse after correcting defect
that caused fuse to blow.
6) Replace SS PC board assembly.
1) Replace the pulse motor which
shows an abnormality.
2) Replace NP board assembly.
3) Replace fuse after correcting defect
that caused fuse to blow.
4) Replace power supply unit
assembly.
5) Replace main PC board assembly.
1) Adjust or exchange SS (VR) PC
board assembly.
2) Check foot control unit operation.
3) Replace LCD module.
1) Adjust balance wheel position.
2) Check connector connection.
3) Replace main motor.
4) Replace SS PC board assembly.
5) Check fabric thickness detection or
replace fabric thickness sensor
assembly.
6) Replace main PC board or power
supply unit assembly.