Bang & Olufsen BeoVision 7 MK II, Руководство по обслуживанию

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2.8 Fault flow chart
No backlight
Measure Power supply to
backlight LCD from PCB4
- - - - - - - -
+24V at 4FP 42, 43 or 44
or
4P6 pin-5
- - - - - - - -
Output from PCB4
Measure CTRL signal
BL_SUPPLY to PCB4
- - - - - - - -
>+4V at 4FB 4 or
4P67 pin 5
- - - - - - - -
CTRL signal from PCB = ON,
Cable: W0, BL power supply
Measure power supply
to backlight LCD
- - - - - - - -
+24V at 8P pin 0-4,
pin 5-9; GND
- - - - - - - -
Output from PCB4,
Cable: W6
Measure power supply
to backlight LCD
- - - - - - - -
+24V at 8P2 pin -5,
pin 6-; GND
- - - - - - - -
Output from PCB4,
Cable: W6
Check cable W6
- - - - - - - -
Connection OK?
- - - - - - - -
Connection W6
PCB4 to PCB8
Replace Main chassis
(Module 999)
- - - - - - - -
Fault may be located
in either PCB4 or PCB
Replace PCB8
- - - - - - - -
PCB8 is defect
Reestablish or replace
the connection
- - - - - - - -
Fault may be in the
connection
Measure CTRL signal
LCD ON
- - - - - - - -
>+4V at 8P pin3
- - - - - - - -
CTRL signal from PCB5
= ON, circuit on PCB8
and cable W6
Measure CTRL signal
LCD ON
- - - - - - - -
>+4V at 8P2 pin2
- - - - - - - -
CTRL signal from PCB5
= ON, circuit on PCB8
and cable W6
Measure CTRL signal
LCD ON
- - - - - - - -
>+4V at 5FP2
pin2
- - - - - - - -
CTRL signal from
PCB5 = ON
Replace Main chassis
(Module 999)
- - - - - - - -
Fault is located in the
Main chassis
Check cable W7
- - - - - - - -
Conection OK?
- - - - - - - -
Connection W7 LCD
to PCB5
Replace PCB8
- - - - - - - -
PCB8 is defect
Action
- - - - - - - -
Confirm
- - - - - - - -
Checked
Check cable W6
- - - - - - - -
Connection OK?
- - - - - - - -
Connection W6, PCB5
to PCB8
Check cable W5
connected ad LCD
- - - - - - - -
Connection OK?
- - - - - - - -
Connection W5 LCD
to PCB5
Reestablish or replace
the connection
- - - - - - - -
Fault may be in the
connection
Fault may be located in
either Main chassis or
LCD panel
Replace Main chassis
(Module 999)
LCD defect
2
3
4
0
20 2
30 3
5
Reestablish
connection
No
Yes