Bang & Olufsen BeoPlay V1-40 MKII Service Manual page 21

From page
3.4
Confirm voltage on
PCB01, P103 pin 12,
Replace PCB01,
PS_BLV_ON approx.
Video Engine
= +5V (high)
OK?
Confirm voltage on
PCB01, P123 pin 4, LCD_INV_BL_ON/OFF
approx. = +5V (high)
and on PCB01, P123 pin 1, LCD_CTRL_PWM,
approx. between 0.9 and 3.3 V
OK?
Confirm voltages on
PCB04, P116 pin 1,
2, 3, 4, 5
Replace PCB04,
P24V = 24V
Power Supply Unit
(or use similar
testpoints)
OK?
See
page
3.6
Checking backlight:
Check light from Backlight LED as indicated below
When switching on TV after stand-by and backlight is missing (or e.g. is missing after a while) and sound is OK.
Problem may disppear after a new stand-by (error ocurrung intermittently). Check the following to reveal fault.
Recommended check points:
BL_ON BL_Err
(4.4V to 4.8V, (3.7V, OK high)
OK high)
4.4 to 4.8V 3.7V
0V 3.7V
4.4 to 4.8V 0V (low)
4.4 to 4.8V 0V (low)
4.4 to 4.8V 0V (low)
Replace PCB01,
Video Engine
LTA400HF33
12VCC 24V Remarks on condition
(internal from PSU
PCB49)
12V 24V Backlight OK
12V 24V Condition: "Picture mode" is activated; BL_ON = 0V and
LED indicator lights green:
Check if cable W24 is OK an connected correctly, PCB01 fails
12V 24V PCB49 or connection to LCD fails (Error on LCD is very seldom)
0V 24V PCB49 defective
0V 0V PCB04 defective; if BLC_ON is 3.2V (PCB04, P18 pin 14)
Fault flow chart 3.5
No
Yes
Hint:
Measurement plugs,
pins and test points;
see page 3.17