Bang & Olufsen BeoLab 12-3, Service Manual

Page: 22 / 60

2.16 Fault flow chart
Fault symptom:
Distorted audio from one or more speaker(s)
Possible causes:
Defective PCB04, SMPS
Defective PCB30, Digital Sound Engine
Defective PCB35, ICEpower amplifier
Defective speaker unit
No
Yes
Distorted sound
from all speakers?
Locate/disconnect the
distorted speaker unit
Connect the speaker unit
to one of the other
amplifiers
Sound OK?
Replace defective
speaker unit
Use ServiceTool to
calibrate the new
speaker unit
Defective PCB35,
ICEpower amplifier
Replace and use
ServiceTool to
calibrate the new
module
Connect the cable
for ServiceTool to
the service
connector. Any
useful information
(error history/usage
data)?
Replace the
suspected speaker
unit(s) related to
the error log
Confirm:
+33V at PCB04, P3
pin 4
-33V at PCB04, P3
pin 2
OK?
Replace defective
PCB30, DSE
Disconnect W3
from PCB04, P3.
C33V at
PCB04, P3 pin 4
-33V at PCB04, P3
pin 2
OK?
Replace defective
PCB04, SMPS
Fault in one of the
three PCB35,
ICEpower amplifiers
Disconnect one by
one and replace the
defective module
Is the fault related
to speaker units?
Replace the
suspected amplifier
module(s) related to
the error log
PCB04, P4, pin information - see next page