LG GX / SPN5-W - Page 39

3-6
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ONE POINT REPAIR GUIDE
C300
100nF
R324 39K
(1%)
C302
100nF
C3K3
1uF
C303
100nF
R328
1.5M NC
3.3VA
R325 2.7K
(1%)
C3K6
100nF
DGND
R326 33
L310
10UH
R379
13K
(1%)
C3K4
1uF
R381 150K
C3H9 10uF
/25V(L)
DGND
C3K5
10pF
C3H8
100nF
DGND
C340 10uF
/25V(L)
DGND
R378
390K
R380
100K
IC311
1
VIN
2
SW
3
GND4
BST
5
EN
6
FB
C341 10uF
/25V(L)
C3K1
10uF
12VA
C3K2
10uF
FB316
R377
0OHM
VOUT = 0.798x(41.7K/13K+1)= 3.36V
[12VA to 3.3VA]
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NO BOOTING WHEN YOU TURN THE UNIT ON, NO MESSAGE OR “HELLO”
ON FRONT PANEL
When you turn on your set, it will blank / no message on front panel / doesn’t work.
1-3. IC311 System 3.3 V in Main Board (No 3.3 VA)
1-3-1. Solution
Replace MAIN board.
1-3-2. How to troubleshoot (Countermeasure)
1) Please check 3.3 VA of IC311 pin2 L310.
2) If 12 VA is OK, but 3.3 VA is abnormal at pin2 L310 of IC311 (VOUT), IC311 block has problem.
1-3-3. Service hint (Any picture / Remark)
< MAIN board top view >
IC311
IC311
L310
L310
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