Line Array Tests - Bose Personalized Amplification System Troubleshooting Manual

9.4 Reference a dB meter to the output level
at the Bass/Amp 3 OUT jack. Remove the
input signal and measure the A-Weighted
output level. It should be -80dB minimum.
9.5 Repeat steps 9.1 to 9.4 for the channel 4
Line input.

Line Array Tests

Connect the Line Array section you are
testing to an amplifier using the test cables
described in the appendix of this trouble-
shooting guidel.
1. Air Leak Test
1.1 Apply a 100 Hz, 10 Vrms sine wave to
the unit under test.
1.2 Listen carefully for air leaks from around
the end cap, the transducers and the grille.
Air leaks will be heard as a hissing or sput-
tering sound. All repairs must be hidden.
Test duration should be 5 seconds minimum.
2. Transducer Rub and Tick Test
2.1 Remove the transducer you wish to test
using the disassembly procedures in this
manual. Do not unplug the wires at the
transducer assembly terminals.
2.2 Connect a signal generator directly to the
terminals of the transducer assembly under
test.
2.3 Apply a 20 Hz, 5 Vrms signal to the
transducer assembly.
2.4 Listen carefully for any extraneous
noises such as rubbing, scraping or ticking.
TEST PROCEDURES
30
Note: To distinguish between normal sus-
pension noise and rubs or ticks, displace the
cone slightly with your fingers. If the noise
stays the same, it is normal suspension
noise and the driver is good. Suspension
noise will not be heard with program mate-
rial.
3. Transducer Phase Test
3.1 Apply a DC voltage of 10V, positive
applied to the positive terminal of the line
array test cable and GND applied to the
GND terminal.
3.2 Notice carefully that all driver cones
should move outward when the DC voltage
is applied.
3.3 Rewire any incorrectly connected trans-
ducers.
4. Line Array Sweep Test
4.1 Connect the line array section under test
to the output of an amplifier being driven by
an audio signal generator. Use the line array
test cables described in the appendix of this
troubleshooting guide.
4.2 Apply a 10Hz, 10Vrms sine wave to the
input.
4.3 While listening to the output of the
system, sweep the input frequency slowly
from 20Hz to 20kHz. Test duration should be
10 seconds minimum.
4.4 Listen carefully for any extraneous
noises such as buzzing and ticking.