Bose FREESPACE BUSINESS Service Manual - Page 20
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Satellite Test Procedures
NOTE: Use these procedures only when
satellites come in to be serviced (without the
bass module).
1. Sweep Test
A. Connect an oscillator to a power amplifier.
Adjust the amplifier output to 4 Vrms. Connect
the amplifier leads to the satellite (cube speaker)
input terminals. Sweep the oscillator from 200 Hz
to 5 kHz. If any twiddler buzzes or sounds
distorted,replace it.
2. Phase Test
NOTE: Supply voltage should only be
momentarily applied to the satellite input
terminals to avoid possible damage to the
twiddlers.
A. Set a DC power supply to 2 volts. To ensure
that each twiddler is connected in phase, connect
the positive supply lead to the positive (+)
satellite input terminal (red) and the negative
supply lead to the negative (-) satellite input
terminal (black). The twiddler should move
outwards with the application of the supply
voltage.
NOTE: If any twiddler cone deflects inwards or
does not move,check all connections.
Bass Module Test Procedures
NOTES: Use these procedures only when a
module comes in to be serviced (without
satellites). All tests should be performed with the
bass and treble control knobs in the normal or
"detent" position. Remove the junction box cover
using Procedure 3 in the Disassembly/
Assembly Procedures section in order to
access the connection terminals for this unit.
TEST PROCEDURES
1. Sweep Test
2. Tone Control Test
19
NOTE: This test can be performed with a fully
assembled bass module.
A. Connect an oscillator to the module's L/R
audio input terminals. Adjust the oscillator to 100
Hz,185 mVrms. Sweep the oscillator from 10-
300 Hz. There should not be any
loud,extraneous sounds. If there are any loud
buzzes or distortion, the woofer may be
defective. The Main PCB (amplifier) should also
be checked for possible problems.
NOTE: There should not be any buzzes or rattles
from within the module. Redress any wire or
component that buzzes or rattles.
NOTE: This test can be performed with a fully
assembled module.
A. Connect an oscillator to the module's L/R
audio input terminals. Adjust the oscillator to 100
Hz,185 mVrms.
B. Rotate the bass control knob fully clockwise
and counterclockwise from its center or "normal"
position. The bass level should increase and
decrease cleanly without making a scratchy
noise. Clean or replace any potentiometer that
makes this noise.
C. Repeat this procedure for the treble control
using a frequency of 4 kHz.
NOTE: Refer to Figures 1 and 2 for an
approximate bass and treble response for this
procedure.