Bose AV28 Manual page 36

Adjustment/Performance Verification Procedures
FM Tuner General Test Setup
Connect the signal generator to the FM an-
tenna jack J102 using a 50 to 75 Ohm match-
ing network. Adjustments to the procedure's
stated signal levels should be made to account
for a signal level loss due to the matching
network and/or any other losses.
4. FM IF Offset Adjustment, TAP
4.1 Issue the TAP command TF.
4.2 Set the RF generator to 98.1 MHz, no
modulation, 50 dBf, at the unit's FM antenna
input, J102.
4.3 Issue TAP command T7.
4.4 Wait two seconds after issuing the TAP
command T7 and then switch the RF genera-
tor to 1 kHz mono modulation, pilot off, 75
kHz deviation.
4.5 Measure the signal at the record output. If
it is < 0.55% THD, proceed to step 4.5. If the
distortion is > 0.55% THD, issue the TAP
command T9. Verify that the THD is now
< 0.55%.
4.6 Issue the TAP command TB. This will
save the adjustment into FLASH.
5. FM Distortion Adjustment
5.1 Set the RF generator to 98.1 MHz, 1 kHz
mono modulation, pilot off, 75 kHz deviation,
65 dBf at the unit's FM antenna input, J102.
5.2 Adjust the unit to 98.1 MHz.
5.3 Measure the signal distortion and level at
the record output. The output signal should
measure <.5% THD+N and at a level be-
tween 520-1050 mVrms.
5.4 If the distortion is >.5%, adjust T103 for
minimum distortion. Verify the signal level is
between 520-1050 mVrms and the distortion
is <.5%.
6. FM Sensitivity Verification
6.1 Set the RF generator to 98.1 MHz, 1 kHz
mono modulation, pilot off, 75 kHz deviation,
17 dBf at the unit's FM antenna input, J102
(19 dBf for Euro).
6.2 Measure the THD+N at the left or right
record output. It should be < 3.0%.
7. Stereo Separation Verification
7.1 Set the RF generator to 98.1 MHz, 1 kHz
left only modulation, 10% pilot, 75 kHz total
deviation, 65 dBf at the unit's FM antenna
input, J102.
7.2 Reference a dB meter to the left record
output.
7.3 Switch the RF generator to right only
modulation.
7.4 Measure the left record output. It should
be < -25 dB, referenced to the measurement
taken in procedure 7.2.
8. FM Stop Level Adjustment, TAP
8.1 Issue the TAP command TF.
8.2 Set the RF generator to 98.1 MHz, 1 kHz
mono modulation, pilot off, 75 kHz deviation,
30 dBf, at the unit's FM antenna input, J102.
8.3 Issue the TAP command T3.
8.4 Switch the RF generator to 98.9 MHz, 35
dBf at the units FM antenna input, J102.
8.5 Place the unit into seek and verify that it
stops at 98.9 MHz.
8.6 Reduce the RF generator to 25 dBf at the
units FM antenna input, J102.
8.7 Place the unit into seek. Verify the radio
does not stop at 98.9 MHz.
8.8 Issue the TAP command TB. This will
save the adjustment into FLASH.
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