Vfd Doesn't Display - LG MDD105 Service Manual

ONE POINT REPAIR INSTRUCTION

2. VFD DOESN'T DISPLAY

Timer doesn't work(abnormal display).
2-1. D13
2-1-1. Solution
Replace D13 on SMPS board.
2-1-2. How to troubleshoot (Countermeasure)
1) Check J1 pin3 -26 V at power.
C2
uF/50V L1 22uH
1000uF/16V
U2 78R12
C7
3 4
GND CON
1000uF/25V
1 2
IN OUT
U4 278R33
1 2
IN OUT
3 4
GND CON
R4 1k
C13
100uF/25V
R8 1k
1 2
W3 Jumper
Q4
KTC3205
C20
330uF/16V
2-1-3. Service hint (Any picture / Remark)
1 2
W1 Jumper
U1 78R05
1 2
IN OUT
3 4
GND CON
C5
C8
100uF/16V
R2 10k
1 2
W12 Jumper
C11
100uF/6.3V
R5
18k
Q2
KTA1273
1 2
W4 Jumper
R10
560
C6
1 2 2 1
100uF/6.3V W11 Jumper W10 Jumper
Q1
KTC3205
C16
47uF/50V
R6
R7 10k
1k
D13
3V
Q3 C15
KTA1268
47uF/50V
3-4
W2
Jumper
8P
8.GND
8
7.CD_CTRL
7
6.PWR_CTRL
6
5.PWR_SENS
5
4 4.5.6V
3
3.VKK
2
2.FL-
1
1.FL+
J1
W14
Jumper
D9 D10
1N4148 1N4148
W8
Jumper
1.GND
J2
2.GND
3.GND
1
4.-12V
2
3 5.+12V
4
6.+12V
5
7.5V
6
8.5.9V
7
9.3.5V
8
10.3.5V
9
10 11.GND
11
12.GND
12
13.36V
13
14.36V
14
15.36V
15
15P
W9
Jumper