Bang & Olufsen BeoLab 18, Service Manual

Page: 13 / 66

Fault flow chart 2.7
Fault symptom:
LED indicator is flashing slowly orange
(the product is close to overheating)
Possible causes:
Defective PCB30, Digital Sound Engine
Defective PCB35, Amplifier
Defective PCB48, NTC Tweeter
Defective PCB48, NTC Woofer
Defective speaker unit
No
Yes
Survey of plugs and pins - see page 2.13
Disconnect product
from mains, wait 2
minutes and
reconnect to mains
OK?
Disconnect the product
from mains.
Disconnect PCB48, P1 on tweeter
and woofer and confirm 470kΩ at
PCB48, NTC P1 pin 1-2
OK?
Read out the
temperature of the
woofer
Seems normal?
Replace Defective
PCB48, NTC
Measure the DC
resistance of the woofer
(wires disconnected):
Woofer = 11.2Ω ± 1.2Ω
OK?
Read out the
temperature **
Seems normal?
Replace PCB35,
Amplifier
Use ServiceTool to
calibrate the new
module
Replace the
suspected module
related to the high
temperature
Replace PCB30,
Digital Sound
Engine
Replace defective
woofer
Use ServiceTool to
calibrate the new
speaker unit
**
Board temperature - PCB30, Digital Sound Engine
Power Supply temperature - PCB04, Power Supply
Amplifier temperature - PCB35, Amplifier
Tip
Use ServiceTool to read out
Error Log.
Replace the suspected module
related to the Error Log
Read out the
temperature of the
tweeter
Seems normal?
Measure the DC
resistance of the tweeter
(wires disconnected):
Tweeter = 6.3Ω ± 0.6Ω
OK?
Replace PCB35,
Amplifier
Use ServiceTool to
calibrate the new
module
Replace defective
tweeter
Use ServiceTool to
calibrate the new
speaker unit