LG MDD105 Service Manual page 21

ONE POINT REPAIR INSTRUCTION
When you turn on the set, the disc tray won't work.
3-2. U4 and D8
3-2-1. Solution
Replace U4_278R33 and D8 on SMPS board.
3-2-2. How to troubleshoot (Countermeasure)
1) Check all of voltage.
2) 3.3 V abnormal.
1 2
W7 Jumper
C3
103/630V
U3
5 8
Vstr DRAIN
2 7
Vcc DRAIN
4 6
Ipk DRAIN
1 3
GND Vfb
FSFM260N
D11
FR104
C14
47uF/50V
D16 FR104
W17
umper
3-2-3. Service hint (Any picture / Remark)
1 10
1 10
D4 SR306
R1 1000uF/16V
56k/2W
9
9
3
3
D5 D7 SHG2D
UF4007 8
8
2
2
D8 SR306
7
7
R3
4 12
4 12
10
13
13
D12
R9
5 11
5 11
1 D15
15
15
C4
U2
C7
3
1000uF/25V
1
U4 278R33
1
IN
3
GND
C10
1000uF/16V
C12
100uF/50V
C13
100uF/25V
FR104
FR104
1 2
W3 Jumper
KTC3205
3-6
1
IN
3
GND
C5
1000uF/16V
78R12 100uF/16V
4
GND CON
2
IN OUT
R2 10k
2
OUT
4
CON
C11
100uF/6.3V
R4 1k R5
18k
Q2
R8 1k
KTA1273
Q4
2
OUT
4
CON
C8
W