Read Sony KDL-37BX401 Service Manual online
Troubleshooting-3
Check video steps
Does OSD display
on screen?
on screen?
No
Check INVERTER
power & T-CON power
power & T-CON power
Check if signal cable was connected
correctly and has signal output
correctly and has signal output
Yes
Yes
Which input has
no signal?
no signal?
Check if PSU CN6402 has
24V output for INVERTER
24V output for INVERTER
Check if PSU CN6401 has
T-CON_VCC_12V output
T-CON_VCC_12V output
Check MB CN201 pin12
BL_ON/OFF
BL_ON/OFF
Hi Æ Backlight ON
Low Æ Backlight OFF
Low Æ Backlight OFF
RF
Check tuner’s
power & signals
power & signals
2.Check if U701 pin13,
pin14, I2C signal is OK
pin14, I2C signal is OK
1.Check if MB U207
has 5V output
has 5V output
AV
Check signal path
from connector to
MB U401
from connector to
MB U401
1.Check C630 for AV1
2.Check C612 for AV2
VGA
Check signal path
from connector to
MB U401
from connector to
MB U401
1.Check C647 for VGA_R
2.Check C649 for VGA_G
3.Check C653 for VGA_B
3.Check C653 for VGA_B
5.Check R676 for VGA_VSYNC
4.Check R672 for VGA_HSYNC
COMPONENT
Check signal path
from connector to
MB U401
from connector to
MB U401
1.Check C603 for Y
2.Check C606 for Pb
3.Check C611 for Pr
HDMI
Check signal path
from connector to
HDMI switch U4051
from connector to
HDMI switch U4051
1. Check HDMI SW (U4051)
input and output TMDS signal
input and output TMDS signal
2. Record equipment part
number for easy duplicate
number for easy duplicate
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