![background image](http://html.mh-extra.com/html/lg/cm9750/cm9750_service-manual_215932047.webp)
3-28
ELECTRICAL TROUBLESHOOTING GUIDE
2. SYSTEM PART
Power on.
System part OK.
Check FFC cable.
Check SMPS board.
Check FFC cable.
Check MAIN board.
Check SMPS board.
Replace VFD301.
FL+/- & VKK voltage OK?
Replace LED
(LD311, LD313),
(LD301, LD303)
Check MAIN board.
“HELLO”
Display on MLD
OK?
Top LED
(LD311, LD313),
(LD301, LD303)
Turn on?
When turn
the volume, count is
change?
NO
NO
NO
NO
NO
NO
NO
NO
NO
CN605
cable connection
OK?
CN605 pin24
+12 V OK?
Check
CN605 pin5, 6
I2C data OK?
CN605
pin8, 9, 10 data signal
OK?
CN605
pin14, 15, 16, 24 power
OK?
YES
YES
YES
YES
YES
YES
YES
YES
Summary of Contents for CM9750
Page 15: ...2 2 ...
Page 19: ...4 SPEAKER SECTION A60L A60R ...
Page 75: ...3 71 3 72 PRINTED CIRCUIT BOARD DIAGRAMS 1 SMPS P C BOARD TOP VIEW ...
Page 77: ...3 75 3 76 2 MAIN P C BOARD TOP VIEW ...
Page 78: ...3 77 3 78 MAIN P C BOARD BOTTOM VIEW ...
Page 79: ...3 79 3 80 3 FRONT P C BOARD TOP VIEW ...
Page 80: ...3 81 3 82 FRONT P C BOARD BOTTOM VIEW ...
Page 81: ...3 83 3 84 4 FRONT_CTRL P C BOARD TOP VIEW BOTTOM VIEW ...