Bang & Olufsen BeoLab 9 Service Manual download pdf (Page 10)

2.4 Fault ﬂow chart

Fault symptom:

- No sound, but green LED is OK

Possible causes:

- Module 999, Ampliﬁer

Is there no sound, but the green LED is OK?

Go to box

further down

on page

Replace Module 999,

Ampliﬁer

From above

No

Yes

Note:

It wil give the best result if it is possible to

use an audio test CD with pure sine waves

and an oscilloscope, when measuring on

the woofer or midrange.

Warning:

Be very careful, when measuring on the

woofer, because there is approx 35Vdc on

both input terminals. Make sure to use a

differential probe, or make sure that the

oscilloscope and the product is not

connected to earth.

Fault symptom:

- No sound from woofer, but tweeter and

midrange is OK

Possible cause:

- Woofer

- Module 999, Ampliﬁer

Turn volume on the Audio Master up to 50.

Conﬁrm an AC-Sound signal by means of the

Bar-graph on the multimeter or an oscilloscope,

when measuring across the woofer input

terminals.

From previous

page

Visual conﬁrm cable

connection between

woofer and Module

999, Ampliﬁer

Reconnect/replace

cable

Remove mains from the

product. Remove the black wire

from the woofer. Measure the

resistance across the woofer

terminals:

Approx 2.9 ohm?

Replace woofer

Replace Module 999,

Ampliﬁer

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 ... 39 40

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