Sony XBR-75X945C, Service Manual

Page: 138 / 209

XBR-65X930C, 75X940C, 945C
138
TROUBLE SHOOTING
1) Power Off Checking*1
(1) K-PWB
PVDD-GND short ?
(See Note 2)
Power Off Check*1
Replace K-PWB
No Measure the Speaker
impedance by multi-meter
Less than 3Ω ?
Yes
Confirm the speaker
harness
Cut or shorted
to the chassis ?
Replace Speaker
No
Yes
Replace Speaker Harness
No
Yes
Return to LED 3x blinking
or Power Off Checking*3
(2) K-PWB
LDO out short ?
(See Note 2)
(3) K-PWB
Fuse broken ?
(See Note 2)
No
Yes
No
Yes
Power Off Check*3
Segment “XS”?
(1) B-PWB
PVDD-GND short ?
(See Note 1)
Replace B-PWB
No
Yes
(2) B-PWB
LDO out short ?
(See Note 1)
(3) B-PWB
Fuse broken ?
(See Note 1)
No
Yes
No
Yes
Yes
No
(3) Fuse open check
Measure impedance of fuse F7700, F7702 5A (12.5V)
If fuse open
→ NG
(1) PVDD-GND short check
Measure impedance between PVDD and GND at C7706,
C7707.
If impedance is <100Ω → NG
(2) LDO out short check
Measure impedance b3.3V and GND at C9130.
If impedance is <100Ω → NG
(3) Fuse open check
Measure impedance of fuse
F7702, F7704, F7705, F7701 5A (12.5V)
F7700 3.15A (DDC5V)
If fuse open
→ NG
(1) PVDD-GND short check
Measure impedance between PVDD and GND at C7722, C7762, C7782,
C7834.
If impedance is <100Ω → NG
(2) LDO out short check
Measure impedance b3.3V and GND at
C7909.
If impedance is <100Ω → NG
Note 2: Note 1: