Radio Alignment Procedure; Preparation; Alignment Procedure - Multitone FLA 872 Technical Manual

TLA 852/FLA 872
5.8

RADIO ALIGNMENT PROCEDURE

5.8.1

Preparation

a) Remove the Board Assembly from the Case (see paragraph 5.5.2).
b) Install a 0 ohm resistor or a shorting link in the position for R456, to disable
the BEC.
c) Disable the AGC circuit by connecting TP403 to 0 volts. Alternatively, lift
R409.
SIGNAL
GENERATOR
5.8.2

Alignment Procedure

a) Configure the test equipment as shown in Figure 5.11. Set the signal
generator to the channel frequency with an output of -10dBm.
b) Put the Board Assembly in the tray of the P671A Alignment Jig and connect
the frequency counter probe to TP405. Adjust CV405 to give a reading of
455kHz ±50Hz at the frequency counter.
c) Adjust CV406 for maximum amplitude of the 455kHz signal on the
oscilloscope. A minimum of 500 millivolts should be achieved.
d) Remove the AGC disable and assemble the Board Assembly in the case.
Remove the right hand label from the case back to expose the aerial trimmer.
Page 5 - 22
1kHz MODULATION
INPUT
AUDIO OUT
RF IN
10dB
ATTENUATOR
Figure 5.11: Radio Alignment Test Equipment
SINAD
METER
455kHz
P671A
HF
COUNTER
OSCILLO-
SCOPE
TM1205 Issue 2