How To Adjust Electron Elements 1. When Power Is Turned On, The Lamp Does Not Light Up; Main Motor Does Not Operate; Operation Of Main Motor Is Not Stable Or Maximum Speed Operation Is Not Possible - Brother STAR240E Service Manual

∗ You must turn off the power and remove connectors from printed circuit boards before measuring resistance.
PROBLEM CAUSE
When power is 1. Plug in the AC cord. Is there 230 VAC across the
1.
turned on, the
lamp does not
light up. 2. When the power is switched ON, is the resistance
3. Is a fuse blown?
4. Is the lamp blown? Remove the lamp, then measure
5. Is the transistor output normal? Remove connector
6. Others
Main motor 1. Does the pulley turn easily?
2.
does not
operate. 2. Is the resistance across the motor connector
3. Is the Start/Stop switch normal?
4. Is the reverse sewing switch normal?
5. Is the resistance 1Ω max. between 2-3 of CN4 on the
6. Others
Operation of 1. When you turn the pulley by hand, does the rotation
3.
main motor is
not stable or 2. Are the sensor PC board assembly and main PC
maximum
speed
operation is not 3. Is the resistance across the motor connector
possible.
4. When the power is switched ON and the speed
5. Is the speed shutter dirty?
6. Is the timing belt tension correct?
7. Others
source connector?
across the resistor less than 1Ω?
the resistance across it. 30Ω max.
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?
(MOTOR) CN9 25-40Ω?
Resistance between 1-4 on the SS-VR PC board
assembly connector
On..........1Ω max.
Off..........Infinite
Resistance between 1-2 on connector CN3 (yellow)
On..........1Ω max.
Off..........Infinite
pin jack assembly PC board when the foot controller
is not plugged in?
vary between extremely hard and easy?
board assembly installation normal?
Are they floating loose or tilted?
(MOTOR) CN9 25-40Ω?
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?
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CORRECTION
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.
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.
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.