Bose L-Bracket 203 Service Manual - Page 6

Browse online or download pdf Service Manual for Speakers Bose L-Bracket 203. Bose L-Bracket 203 14 pages. Loudspeaker l-bracket
Also for Bose L-Bracket 203: Installer's Manual (7 pages), Installation Instructions (2 pages)

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Power Amplifier

Frequency

Generator

Figure 1. Model 203™ Loudspeaker test

setup diagram

Note: Refer to Figure 3. Model 203 driver

wiring diagram for the following procedure.

1. Phase test

1.1 Remove the speaker grille using

procedure 1.

1.2 Observing polarity, apply a +6Vdc level

to the input terminals on the rear of the

loudspeaker. The speaker drivers should

both move outward.

1.3 Replace the grille using procedure 2.

Note: Refer to Figure 1. Model 203

Loudspeaker test setup diagram, for the

following tests.

2. Rub and tick test

2.1 Remove the grille using procedure 1.

2.2 Apply a 6 Vrms, 10 Hz signal to the

input terminals on the rear of the speaker

cabinet.

2.3 Listen carefully for any buzzes, rattles,

or other extraneous noises from the drivers

or trim parts.

Note: There is a normal suspension noise.

To distinguish between a rub or a tick and

suspension noise, displace the driver cone

slightly with a finger. If the noise stays the

same, it is suspension noise.

TEST PROCEDURES

DMM

Loudspeaker

2.4 Replace the grille using procedure 2.

3. Air leak test

3.1 Remove the grille using procedure 1.

3.2 Apply a 6Vrms, 60Hz signal to the

input terminals on the rear of the speaker

cabinet. Leave the speaker port open.

3.3 Test duration should be 5 seconds

minimum.

3.4 Listen carefully for air leaks along all

glue joints, at the binding post connector,

and at both transducer mounting locations.

Air leaks will be heard as a hissing or

sputtering sound. All repairs must be

hidden.

3.5 Replace the grille using procedure 2.

4. Power sweep test

4.1 Apply a 6Vrms, 10Hz signal to the

input terminals on the rear of the speaker

cabinet. Leave the speaker port open.

4.2 Sweep the input frequency from 10Hz

to 3 kHz.

4.3 Reduce the input voltage level to

4Vrms and sweep the oscillator from 3kHz

to 5kHz.

Note: The whooshing noise from the port

at approximately 60Hz is acceptable.

4.4 Replace any transducer that has a

buzzing noise. There shall not be any

buzzes or rattles from the internal

connecting wires or components.

Redress any buzzing wires.