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You must turn off the power and remove connectors from printed circuit boards before measuring resistance.
PROBLEM
CAUSE
CORRECTION
1.
When power is
turned on, the
lamp does not
light up.
1. Plug in the AC cord. Is there 120 VAC across the
source connector?
2. When the power is switched ON, is the resistance
across the resistor less than 1
Ω
?
3. Is a fuse blown?
4. Is the lamp blown? Remove the lamp, then measure
the resistance across it. 30
Ω
max.
5. Is the transistor output normal? Remove connector
CN1 from the motor control board and measure the
voltage between 1 and 2 on connector CN1 when the
power is switched ON. Is the voltage about 13 VAC?
6. Others
1. Replace the cord reel or
replace the main PC board
assembly.
2. Replace the main PC board
assembly.
3. Replace the fuse (after
eliminating the cause for its
having blown) or replace the
main PC board assembly.
4. Replace the lamp.
5. Replace the main PC board
assembly.
6. Replace the main PC board
assembly.
2.
Main motor
does not
operate.
1. Does the pulley turn easily?
2. Is the resistance across the motor connector
(MOTOR) CN9 25-40
Ω
?
3. Is the Start/Stop switch normal?
Resistance between 1-4 on the SS-VR PC board
assembly connector
On.......... 1
Ω
max.
Off.......... Infinite
4. Is the reverse sewing switch normal?
Resistance between 1-2 on connector CN3 (yellow)
On.......... 1
Ω
max.
Off.......... Infinite
5. Is the resistance 1
Ω
max. between 2-3 of CN4 on the
pin jack assembly PC board when the foot controller
is not plugged in?
6. Others
1. Adjust the mechanism so that
it turns easily.
2. Replace the motor.
3. Replace the SS-VR PC board
assembly.
4. Replace the reverse sewing
switch.
5. Replace the main PC board
assembly.
6. Replace the main PC board
assembly.
3.
Operation of
main motor is
not stable or
maximum
speed
operation is not
possible.
1. When you turn the pulley by hand, does the rotation
vary between extremely hard and easy?
2. Are the sensor PC board assembly and main PC
board assembly installation normal?
Are they floating loose or tilted?
3. Is the resistance across the motor connector
(MOTOR) CN9 25-40
Ω
?
4. When the power is switched ON and the speed
adjustment control is slid, does the voltage between
(+) 2 and (-) 1 of the connector on the SS-VR PC
board vary between 0 and 5 VDC?
5. Is the speed shutter dirty?
6. Is the timing belt tension correct?
7. Others
1. Adjust the mechanism so that
it turns easily.
2. Correct the installation.
3. Replace the motor.
4. Replace the SS-VR PC board
assembly.
5. Clean the speed shutter.
6. Adjust the timing belt tension.
7. Replace the main PC board
assembly.