Model 151™ and 111™ ENVIRONMENTAL SPEAKER SYSTEM
SPECIFICATIONS
Transducer: |
Cabinet: |
1-4.5" (11.4 cm) full-range, |
Black or white high-impact molded |
environmental driver |
polypropylene |
Nominal Impedance: |
Speaker Dimensions: |
4 Ohms |
6.1"H x 9.1"W x 5.9" D |
|
(15.4 H x 23.0 W x 15.0 D cm) |
IEC Power Rating: |
Shipping Weight |
Min: 10 Watts Per Channel |
4.0 lbs. (1.8 kg) Per Speaker |
Max: 40 Watts Per Channel |
|
©200 Bose Corporation
Service Manual
Test Procedures
NOTES: In each test procedure, it is necessary to remove the grille to access the driver.
Refer to the Grille Removal procedure.
Polarities are not marked on the input terminals of the 151™ speaker. The red terminal is the positive (+) terminal and the black terminal is the negative (-) terminal. See Figure 1.
1. Rub and Tick Test
A. Connect a sine wave oscillator to a power amplifier. Adjust the frequency of the oscillator to 10 Hz and the amplifier output to 6 Vrms. Connect the amplifier output to the input terminals of the 151 speaker (see Figure 1). No extraneous noises such as rubbing, scraping or ticking should be heard.
NOTE: To distinguish between normal suspension noise and rubs or ticks, displace the cone on the driver slightly with your fingers. If the noise can be made to go away or get worse, it is a rub or a tick and the driver should be replaced. If the noise stays the same, it is normal suspension noise and the driver is fine. Suspension noises will not be heard with program material.
2. Sweep Test
A. Sweep the oscillator from 10 Hz to 3 kHz using the 6 Vrms signal. There should not be any loud extraneous sounds. (Note: A "whooshing" noise from the port at approximately 80 Hz is acceptable). If there are any loud buzzes or distortion, replace the driver. (See
Disassembly/Assembly Procedures for instructions on replacing the driver).
NOTE: There should not be any buzzes or rattles from within the speaker cabinet. Redress any wire or component that buzzes.
B. Reduce the amplifier output to 3 Vrms and continue sweeping from 3 kHz to 15 kHz. If there is any buzzing or distorting,replace the driver (see Disassembly/Assembly Procedures for instructions on replacing the driver).
1
Audio Signal |
Power |
Amplifier |
Generator |
||
|
Input |
Output |
|
- |
- |
+ - |
+ |
+ |
Speaker
+ -
Red (+)
Black (-)
Figure 1. Test Connections 151™ Speaker
3. Air Leak Test
A. Using the 6 Vrms signal,set the oscillator frequency to 10 Hz. Block the ports. For at least 3 seconds, listen for air leaks around the driver and baffle. If there is a "whooshing" noise around the driver, re-position the driver gasket behind the driver to make an airtight seal. If there are similar noises around the baffle, make sure that it is securely fastened to the speaker cabinet.
4. Phase Test
NOTE: Supply voltage should only be momentarily applied to the speaker input terminals to avoid possible damage to the speaker.
A. Set a DC power supply to 10 volts. To ensure that the driver is connected in phase, connect the positive lead of the supply to the positive (+) speaker input terminal and the negative lead to the negative (-) input terminal. The driver should move outwards with the application of the supply voltage.
2
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