BOSE AV28 Schematic

AV28 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 AV28 Troubleshoot-

ing Tips/Preventative Repair Measures document.

®

3. Check the software revision of the unit. Refer to the Bose

http://serviceops.bose.com for information regarding the latest software revision.

3.1 With the system off and powered applied, press “Store” and “Enter”.

4. Verify Performance and all functions using the following procedures.

4.1 Tuner performance procedures.

service extranet site,

4.2 Input/Output performance procedures.

4.3 CD performance procedures.

4.4 User Interface Performance Verification.

Required Test Equipement and Cables

1. Audio Signal Generator.

2. Oscilliscope

3. Volt Meter

4. AM/FM Signal Generator.

5. AV28 remote control part number 256119-001.

6. PS28 or PS48 bass module with cubes (to test digital audio Zone ouputs).

7. AV28 test cable part number 264565.

8. RCA to bare wire cables (to connect cube speakers to bass module).

Rear cable part number 180644; black.
Left/Center/Right part number 180643-4; black.

Note: AC2 connector part number 195505-001 to connect bare wire to Jewel® Cube speaker.

9. Test CDs as listed below or equivalent.

Parameter Nominal Limit Suggested Test disc

Defect Tracking (void) 1.0 mm 0.8 mm Pierre Vernay, test CD#2

Defect Tracking (black dot) 1.0 mm 0.8 mm ABEX test disc TCD-725R

Defect Tracking (scratch) 1.6 mm 1.0 mm ABEX test disc TCD-721 R

Defect Tracking

(finger print)

Defect Tracking

(warped disc)

Defect Tracking

(eccentric disc)

75 mm 65 mm ABEX test disc TCD-725R

1.0 mm 0.7 mm ABEX test disc TCD-732RA

210 mm 140 mm ABEX test disc TCD-714R

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AV28 Performance Verification Procedures

AM Performance Tests

AM Tuner General Test Setup

Setup a loop antenna as shown.

Test Loop

External AM
Loop Antenna
positioned inside
test loop antenna

Figure 1. AM Test Setup

1. AM Sensitivity Test

1.1 Set the RF generator output to 70 dBuV/M,

30% AM modulation, 400Hz and the unit and
RF generator to 1080 kHz.

1.2 Reference a dB meter to the left or right line
level output.

3.2 Measure the distortion at the left or right
line level output. It should be < 3.0%.

4. FM Stop Level Test

4.1 Set the RF generator to 98.9 MHz, 1 kHz

mono modulation, pilot off, 75 kHz deviation, 36
dBuV/M, at the unit’s FM antenna input.

4.2 Place the unit into seek and verify that it
stops at 98.9 MHz.

4.3 Reduce the RF generator to 25 dBf.

4.4 Tune the unit to 98.1 MHz and then place

the unit into seek. Verify the radio does not stop
at 98.9 MHz.

5. Serial Data Verification

5.1 Connect an Oscilloscope to the serial data

output connector J704 pin 2.

5.2 Press volume up or down on the console.
Observe a digital wave form on the oscillo­scope.

1.3 Turn off the RF generator’s modulation.

1.4 The line level output should measure < -20

dB, SNR.

2. AM Stop Level Test

2.1 Set the RF generator to 1130 kHz, AM

modulation, 400 Hz modulation, 65 dBuV/M.

2.2 Place the unit into seek and verify the unit
stops at 1130 kHz.

2.3 Switch the RF generator for a 55 dbuV/M
field intensity and verify the unit does not stop
at 1130 kHz.

3. FM Sensitivity Test

3.1 Set the RF generator to 98.1 MHz, 1 kHz

mono modulation, pilot off, 75 kHz deviation, 46
dBuV/M at the unit’s FM antenna input.

6. TV Sensor Verification

6.1 Apply a signal to the TV Sensor input J105

pin 2 at the level and frequency listed in the
following table. The signal should be applied to
the ring of a 3.5mm jack.

6.2 Measure the output of the detector, U303
pin 8, at J103 pin 19.
Note: Off <.8Vrms, On >2.5Vrms. Settling time
is .1 seconds to turn on, 2.0 seconds to turn
off.

Input

Frequency

Input

Amplitude

Detector

Output

60 Hz 200 mVrms <.8Vrms

15.75 kHz 30 mVrms >2.5 Vrms

31.5 kHz 30 mVrms >2.5Vrms

Note: If a unit fails any of these tests, refer to
the appropriate service manual for alignment
procedures. Replace any defective component
found.

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