No Characters Appear On The Lcd; The Message Keys Do Not Work; The Lcd Contrast Cannot Be Adjusted; The Wrong Pattern Name Appears On The Lcd - Brother BL6200 Service Manual

PROBLEM
17. No characters
appear on the
LCD.
18. The message keys
do not work.
19. The LCD contrast
cannot be adjusted.
20. The wrong pattern
name appears on
the LCD.
CAUSE
1 line LCD
1. Improper setting of LCD contrast key.
2. Disconnection of connector CN 1.
3. Voltage between terminal 2-1 of LW1
on motor control unit is less than
DC5V.
4. Inferior LCD unit.
4 line LCD
1. Improper setting of LCD contrast
manual.
2. Disconnection of connector P1.
3. Disconnection of connector P5.
4. Voltage between terminal 2-1 of LW1
on motor control unit is less than
DC5V.
5. Inferior LCD control PCB or LCD
module.
1 line LCD
1. Message key top does not work.
2. Inferior LCD unit.
4 line LCD (A,B,↓,↑)
1. Each key tops do not work.
2. Inferior LCD control PCB.
1 line LCD
1. LCD contrast key does not work.
2. Improper LCD contrast.
4 line LCD
1. LCD contrast key does not work.
2. Improper LCD control PCB.
1 line LCD
1. Disconnection of connector CN2 on
LCD unit.
2. Inferior LCD unit or pattern sensor.
4 line LCD
1. Disconnection of connector P3 on LCD
control PCB.
2. Inferior LCD control PCB or pattern
sensor.
Adjust LCD contrast key.
Connect CN1 on LCD unit.
Replace the motor control unit.
Replace the LCD unit.
Adjust LCD contrast manual.
Connect P1 on LCD control PCB.
Connect P5 on LCD module.
Replace the motor control unit.
Replace the LCD control PCB or LCD
module.
Check the message key and key top.
Replace the LCD unit.
Check each keys and key tops.
Replace the LCD control PCB.
Check the slide volume and slide key.
Replace the LCD unit.
Check the slide volume and slide key.
Replace the LCD control PCB.
Connect CN2 on LCD unit.
Replace the LCD unit or pattern sensor.
Connect P3 on LCD control PCB.
Replace the LCD control PCB or pattern
sensor.
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CORRECTION
1 line LCD
4 line LCD
1 line LCD
4 line LCD (A,B,↓,↑)
1 line LCD
4 line LCD
1 line LCD
4 line LCD