Bose AM-30P Manuale di servizio - Pagina 33

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18. Bass Module Sweep Test

18.1 Apply a 100Hz, 40mVrms signal to the

module's audio input terminal. Set the bass

control knob (potentiometer R306, Main

PCB) to maximum. Sweep the oscillator

from 40Hz to 300Hz, listening for any

unusual buzz, rub, or extraneous sounds.

Note: There should not be any loud

buzzes or rattles from within the module.

Redress any wire or component that

buzzes or rattles.

19.1 Connect an oscillator to the module's

audio input terminal. Adjust the oscillator to

40Hz, 27mVrms. Listen for air leaks around

the cabinet, paying particular attention to

the area where the base plate seals to the

cabinet. If there is a "whooshing" noise,

there is probably an air leak. Repair air

leaks as required.

20.1 Apply a 100Hz, 40mVrms signal to

the audio input. Rotate the bass control

fully clockwise and counterclockwise from

its center position. The frequency response

should increase and decrease smoothly

without making any scratchy noise. Clean

or replace any control that is noisy.

20.2 Apply a 8kHz, 40mVrms signal.

Rotate the treble control in the same

manner as the bass control. Look for a

smooth response. Clean or replace any

control that is noisy.

TEST PROCEDURES