Sony KDL-43W950C / KDL-50FA95C / KDL-50FA97C / KDL-50W950C Service Manual ▷ View online
33
Troubleshooting
BMX board Side A
Troubleshooting Reference
IC7751
F7751
L7751
L7752
L7753
L7754
C7767
C7768
C7769
C7770
R7877
C7862
C7864
C7866
R7879
CN7751
1 2 3 4
CN
9000
9000
18
16
R7876
R7878
Reference A
34
Troubleshooting
BMX board Side A
Troubleshooting Reference
8
13
19
23
24
R7739
R7736
R7736
R7739
R7738
R7738
5
IC775
1
Reference B
35
Troubleshooting
3-3-2. Main Board Power On Checking (for Main SP Lch & Rch) for BMX board only
No
Checking Item
OK
NG
If NG
If NG
1
Check
IC7751 side-terminal of
L7751,L7752,
L7753,L7754
Switching Freq = 384kHz or 768KHz
±20KHz
Vrms = don’t care
No switching
frequency at
either one of the
CL
Go to next checking.
2
Check F7751 MainSP
(for BMX XM-H board
only)
V(before fuse) = 12.5V ± 0.5V
V(after fuse) = 12.5V ± 0.5 V
No voltage.
Check fuse broken?
Check CN9000 Pin 16
&18 got 12.5V?
Change fuse (5A).
Check power supply
board audio VCC.
3
Check F7751 MainSP
(for BMX XM-A, XM-AT
and XM-DT only)
V(before fuse) = 19.5V ± 0.5V
V(after fuse) = 19.5V ± 0.5V
No voltage.
Check fuse broken?
Check CN9000 Pin 16
&18 got 19.5V?
Change fuse (5A).
Check power supply
board audio VCC.
4
Check IC7751 (Pin 5) at
R7879
(for BMX board only)
V(before R7879) = 3.3V ± 0.5V
V(after R7879) = 3.3V ± 0.5V
No voltage.
Check +3.3V_MAIN
supply.
5
Check R7876, R7877,
R7878
Vdc = 3.3V ± 0.3V
Vdc < 0.8V
R7877 NG,
Check IC7751
R7876, R7878 NG,
Check IC1000
6
Check R7736, R7738,
R7739, and R7740
R7738 = 12.288MHz
R7740 = 3.072MHz
R7739 = 48KHz
R7736 = moving CLK
All Vp-p ≈ 3.3V
If no frequency at
R7738, R7739,
and R7740,
Muffin IC
(IC1000) NG.
If no frequency
at R7736 make
sure sound
source OK.
If sound source OK, but
at R7736 = NG, Muffin IC
(IC1000) NG.
Note : Parts location refer BMX Board : Reference A and Reference B.
No
Checking Item
OK
NG
1
Check fuse F4500, F4501
Fuse short
Fuse open
2
Check connectivity audio Vcc to GND
C4512 – GND
C4532– GND
C4534 – GND
No short to GND
Either 1 short to GND
3
Check connectivity audio +3.3V_MAIN to GND
(only for KK board)
IC4505 (Pin5) at R4533 – GND
No short to GND
Either 1 short to GND
4
Check connectivity audio output to GND.
CN4505
Pin 5 – GND
Pin 6 – GND
Pin 7 – GND
Pin 8 – GND
No short to GND
Either 1 of pin short to GND
5
Check connectivity audio output path
(only for KK
board):
L4500 (near to IC side) – CN4505 Pin8
L4501 (near to IC side) – CN4505 Pin7
L4502 (near to IC side) – CN4505 Pin6
L4503 (near to IC side) – CN4505 Pin5
Must have good connection
(~0 Ω)
Open circuit.
36
Troubleshooting
3-3-3. KK board Power Off Checking (for Dual Acoustic Duct Subwoofer Lch & Rch) for KK board (XM-DT) only
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