Control Box Troubleshooting Guide - Brother MD-602 Service Manual

13.2 Control box troubleshooting guide

Power PCB
PROBLEM
When power SW is ON, LED
(Red) does not illuminate.
While running the motor OV
or OL error sign appears.
Motor does not run
smoothly and an error sign
PT appears, sometimes.
While running, PT appears.
Motor does not run
smoothly.
Motor start up is not good
and motor does not rise in
its rotation. Or, the power
relay becomes OFF.
Treadle unit
Motor does not start when
pressing the pedal
Synchronizer
While running an error sign
Lo appears.
Motor does not run
smoothly. Motor rotate by
doing inching.
CHECK
Fuse F101, F102 blown?
Fuse F101, F102 OK?
CNR (40W/100ohm
broken down?)
F201 (2A fuse) blown?
OL error?
Malfunction by noise
coming from outside.
Malfunction by static
electricity
Operation of IPM
Wirewould resistance of
motor.
Operation of PHU-PHZ
Operation of IPM
Is power relay ON?
Heating of the R101
resistor?
Is VC voltage right at
pedal neutral position?
VC voltage when pedal is
pressed fully forward
VC voltage does not
change?
Remove synchronizer
cord and check opera-
tion. Machine and motor
run
Remove synchronizer
cord and check opera-
tion. No running of
machine and motor
Remove synchronizer
cord and check
It rotate smoothly
It does not rotate
smoothly.
MD-602, 612
PROBABLE CAUSE
Short circuit of the load on the
power circuit. Something wrong
with BD101? IPM? ZR? C101–C103,
C111–C113?
Power transformer?
Has the R101 broken down?
Has the pattern blown?
40W/100ohm broken down?
iGBT broken down?
Pressed the pedal so hard?
Is earth surely taken for the power
supply?
Is earth taken for the sewing head
and box? Is earth good for motor
and box?
Something wrong with IPM, PHU-
PHW
Measure wirewould resistance.
2.6ohm between each phases?
Check IPM operation.
Is the contact point of power relay
open? When the power switch is
ON, the contact point is closed. Is
R101 resistor broken?
Is there about 1.5V?
Is there about 4.5V?
Something wrong with #1?
HO?
No encoder signal, needle-up
signal, needle-down signal.
Motor is locked.
Sewing head is locked.
Others
Something is wrong with the
encoder signals.
Motor is broken down or resis-
tance value abnormal
Others
REMEDY
Do not switch ON unless
short circuit is solved.
Replace the R101
Replace power PCB
Replace 40W/100ohm
Replace fuse, iGBT
Educate how to press the
pedal
Take earth
Take earth
Replace the power PCB
Replace motor
Replace power PCB
Replace relay (RY).
The lead wire of relay is
broken.
Replace R101
Adjust by VR1
Adjust by VR2
Replace #1, HO.
Replace synchronizer
Motor
Adjust sewing head
Control PCB?
Replace synchronizer
Motor
Control PCB
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