SECTION 2: FACTORY TEST PROCEDURE
369548.DOC
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Adjustment / Alignment Procedures
Make appropriate notations of any items that require attention during this procedure. This information is
needed later during the repair process.
Startup
Step 1
Remove the base station cover placing the screws in a location where they will not be
misplaced.
Step 2
Connect the base station to the appropriate components.
Step 3
Power up the base station and computer. The power supply ammeter must read 1.2
amps or less with a 13.8 VDC input.
Receiver Injection
Step 1
Using the HP high frequency probe verify that the receiver injection frequency is present
at each of the three (3) receivers by monitoring the receivers R24 surface mount pad
which lies on the 50 ohm track between P1 and C43.
Step 2
Adjust R23 on the receiver injection circuit board to set the injection frequency within 10
Hz of the exact injection frequency. The amplitude of the injection frequency should read
approxi5 dBm
±
1 dBm.
Receiver
Step 1
Using the high frequency probe, monitor the
44.545 MHz second injection frequency
at U6 pin 3, adjust trimmer capacitor (C22) to the center of the oscillator’s oscillation
range. The amplitude level of pin 3 of U6 should read b5 and +10 dBm.
Step 2
Inject an on-frequency signal at a level of –80 dBm, modulated with a 1 KHz test tone at
±
5.0 KHz deviation into the receiver under test.
Step 3
Check the receiver’s sensitivity, verifying that the SINAD is 12 dB or better at a maximum
level of –119 dBm (-120 is typical).
