BOSE PS18, PS28, PS48 Schematic
PS28/48 General Test Procedures
1. Initial Product Test
Note: Before taking the unit apart or performing any repair process, an attempt to verify the cus-
tomer complaint must be made.
1.1 Read any customer note included with the unit.
2. Attempt to verify the complaint before opening the unit or performing any repairs.
2.1 Customer complaint not verified, discuss with customer.
2.2 Customer complaint verified, troubleshoot and repair the unit. Refer to the PS28/28 Trouble-
shooting Tips/Preventative Repair Measures document.
3. Check the software revision of the unit, using the procedures on page 5, procedure 2.3.
®
Refer to the Bose
service extranet site, http://serviceops.bose.com for information regard-
ing the latest software revision. Update is needed.
4. Verify Performance and all functions.
Note: If a media center is available, use the procedures “With AV28 media center”. if a media
center is not available, use the procedures “Without AV28 media center”.
Required Test Equipment and Cables
1. Audio Signal Generator.
2. Digital Converter (A-D) with S/PDIF output, if AV28 Media Center is not availble.
3. PC (IBM compatible), if AV28 Media Center is not availble.
4. DC power supply for cube phase test.
5. Audio amplifier for cube sweep test.
6. PS28/48 test cable part number 264564.
7. RCA to bare wire cables (to connect cube speakers to bass module).
Black rear cable part number 180644
Black Left/Center/Right part number 180643-4
Note: AC2 connector part number 195505-001 is needed to connect bare wire to Jewel® Cube
speaker.
9 PIN D-SUB FEMALE
Connect to computer
RS232 port
Connect to D-A
converter
RCA PLUG
2
3
6
7
8
Test cable part number 264564
1
8 PIN RJ45
RJ45
8 PIN
Connect to
PS28/48 bass module
PS28/48 Performance Verification Procedures
(Without AV28 Media Center Console)
Test setup procedures
Place the bass module into TAP mode using
the procedures located at the end of this
document.
Note: Place all four DIP switches into the down
position before returning the unit to the customer.
Test cable part number 264564, Figure 16, is
needed to test the bass module.
Connect the D-sub, 9 pin connector on the test
cable to the COM port on your computer.
Connect the RJ-45, 8 pin connector to the
bass module.
The bass module requires a digital audio input.
Connect the analog output of an oscillator to
the analog input of an Analog to Digital (A-D)
converter. Connect the test cable’s RCA
connector to the A-D converter S/PDIF output.
2 Bass Module Air Leak Test
2.1 Apply a 200 mVrms, 40 Hz signal to the
input of the A-D converter.
2.2 Check for air leaks from the cabinet. Listen
near the areas where the plastic seals to the
wood.
3. Cube Speaker Phase Test
Note: The DC voltage should only be momen-
tarily applied to the cube speaker input to avoid
damaging the speakers.
3. 1 Observing polarity, momentarily apply 8 Vdc to
the input of the cube speaker.
3.2 The speakers should move outward with
the application of the dc voltage. Check the
cube wiring if it moves inward.
1. Sweep Test
1.1 Issue the following TAP commands:
SO ALL D (select all digital source inputs)
SP 5 (5 speaker mode)
VO CB 0 (set volume to full output, 0dB)
MU AMP OFF (unmute the amp)
1.2 Apply a 200 mVrms, 25 Hz signal to the left
and right input of the analog to digital (A-D)
converter. Listen for any extraneous noises
such as rubbing, scraping, or ticking.
Note: No extraneous noises such as rubbing,
scraping or ticking should be heard. To distinguish between normal suspension noise, rubs
and ticks, displace the woofer cone with your
finger. If the sound can be made to go away or
get worse, it’s a rub or tick and the woofer
should be replaced. If the noise stays the
same, it’s normal suspension noise and it will
not be heard with regular program material.
1.3 Sweep the bass module from 40 Hz to 300 Hz.
Listen carefully for any buzzes, rattles
or extraneous noises coming from the bass
module.
Note: Redress any wire or component that
buzzes.
4. Cube Speaker Sweep Test
4.1 Apply an 11 Vrms, 20 Hz signal to the
input of the satellite. Change the applied signal
to 8 Vrms, 150 Hz. Sweep the oscillator from
150 Hz to 2 kHz.
4.2 Listen for rubs, ticks, air leaks, buzzes or
other extraneous noises.
Note: Defects such as rubs, ticks and air leaks
will typically be most audible during the 20 Hz
test. Defects such as buzzes will typically be
heard during the 150 Hz to 2 kHz sweep.
Note: The satellite cubes are not repairable.
The Jewel Cube® speakers are repairable.
5. Listening Test
5.1 Connect the cube speakers to the outputs
of the bass module.
5.2 Connect an audio source (i.e. CD player)
to the input of the A-D converter.
5.3 Perform procedure 1.1
5.4 Adjust the volume output of the audio
source to a comfortable level and listen for a
clean undistored audio output from the bass
module and cube speakers.
2
Loading...