Bang & Olufsen BeoLab 20 Service Manual page 12

2.6 Fault flow chart
From
#1
Connect to a source via:
Power Link, TOSLINK or line-in signal
Set role switch to R or L
Replace PCB30,
Confirm Digital Sound
PS_ON = 3.3V at
PCB04, P14 pin 7 Use ServiceTool to
calibrate the new
OK?
Confirm
Replace PCB04,
P15V = 15V at
Power Supply
PCB04, P14 pin 5
OK?
Confirm
+28V at PCB04,
P16 pin 1, 2 and
-28V at PCB04,
P15 pin 8, 9
OK?
Replace PCB35.1,
+28V at PCB04,
Amplifier
P16 pin 1, 2 and
-28V at PCB04,
*
OK?
Connect ServiceTool cable to
Engine
PCB30, Digital Sound Engine
module
OK?
Remount PCB04,
Power Supply and
replace PCB30,
Digital Sound
OK?
Engine
Disconnect W6 from PCB35.1, P3.
Confirm +28V at PCB04, P15 pin 1, 2
and -28V at PCB04, P15 pin 8, 9
OK?
(Reconnect W6 after test)
Confirm Disconnect W8 from PCB35.2, P3.
Confirm +28V at PCB04, P17 pin 1, 2
and -28V at PCB04, P17 pin 8, 9
P17 pin 8, 9
OK?
Replace PCB35.2,
Amplifier
*
SERVICE connector.
Check connection between
PCB02.1, Input Panel and
OK?
Replace PCB02.1,
Input Panel
Replace PCB04,
Power Supply
OK?
(Reconnect W8 after test)
Yes
Repair/replace
connection
OK?
Replace PCB04,
Power Supply
Use ServiceTool to
autocalibrate the
new module
Survey of plugs and pins - see page 2.11
No
*