Test Procedures - Bose Life CD5 Series I Service Manual

AM ALIGNMENT PROCEDURES
Test setup: Connect the generator to a
standard radiating loop. Unless otherwise
noted, set an RF generator to 70dBu field
strength, 400Hz, 30% modulation.
See Figure 9.
STANDARD
SIGNAL
GENERATOR
TEST
LOOP
STANDARD
SIGNAL
GENERATOR
Figure 9. AM Test Setup
The equivalent field intensity is 26dB less
than the generator output level or 1/20
the output voltage.
1. AM Sensitivity Alignment
1.1 Set the RF generator so that the field
strength at the unit's antenna is 70dBµ
(70dBµ V/M).

TEST PROCEDURES

(PLAN VIEW)
60cm
(SIDE VIEW)
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Figure 10. Audio PCB Test Section
26
1.2 Reference a dB meter to the Fixed level
output.
1.3 Shut off the modulation and measure
the noise. The SNR should be > 30dB.
2. AM Stop Level Adjustment
2.1 Set the RF generator so that the field
strength at the unit's antenna is 59dBµ
(59dBµ V/M).
2.2 Rotate R339 counterclockwise until the
voltage measured at U301 pin 21 goes
below 2.5Vdc. Then, rotate R339 clockwise
until the voltage goes above 2.5Vdc.
Note: The correct adjustment is at the point
just after the voltage switches high.
2.3 Adjust the field strength to 64 dBµ
(64 dBµ V/M). Verify that the voltage at
U301 pin 21 is < 2.5Vdc.