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CONDITION
PROBLEM SYMPTOMS
COUNTERMEASURES
3. Pattern
selection is not
possible.
1) Is the start/stop switch stuck?
2) Other
1) Correct, or replace the SS PC board
assembly.
2) Replace the LCD module assembly.
4. Main motor
does not
operate.
1) Does the hand wheel turn easily?
2) Is the main motor assembly connector
(power supply unit connector CN1)
correctly connected?
3) Is the resistance between the terminals of
the main motor assembly normal?
For 120 V models ................ 120 to 180
Ω
For 230 V models ................ 400 to 800
Ω
4) Is the start/stop switch normal?
Resistance between both switch sides:
When switch is pressed .... less than 1
Ω
When switch is released ........
∞
(infinite)
5) Is the presser foot lever down? Is the
presser switch normal?
Resistance between both sides of CN8
Presser foot is up .............. less than 1
Ω
Presser foot is down...............
∞
(infinite)
6) Other
1) Correct installation so hand wheel turns
easily.
2) Confirm connection.
3) Replace the main motor assembly.
4) Replace the SS PC board assembly.
5) Confirm the presser switch installation; if
the problem remains, replace the
presser switch.
6) Replace the main PC board assembly or
the power supply unit assembly.
5. Main motor
operates
unevenly.
1) When the hand wheel is rotated slowly in
reverse, does the voltage between 2-5, 3-
5 and 4-5 in the NP PC board assembly
connector (CN10) fluctuate between 0 to
5 V DC?
2) Other
1) Replace the NP PC board assembly.
2) Replace the main PC board assembly.
