RECEIVER FREQUENCY ADJUSTMENT
(Refer to Transmit Frequency Adjustment, no adjustment of
receive frequency is required.)
ALTERNATE IF SWEEP ALIGNMENT
1.
Attach an oscilloscope probe to IF AMP. MTR. (J602-
10). (Refer to Figure 6).
2.
Using an HP8640B signal generator, set with an on-
channel frequency, feed a 20 Hz modulating frequency
with 12 kHz of deviation into the radio at antenna jack
J2.
3.
Connect a coaxial cable between the AM output of the
HP8640B and the external 10 trigger signal on the
scope. Use NORMAL triggering.
4.
DC couple the scope probe and adjust the controls for
0.1V per div. and 2 msec per div.
5.
Adjust the AM output level to make sure the scope is
triggering. Adjust the RF input signal level to keep the
IF passband sweep pattern just below saturation (typ. 9
µ
V). After using the vertical and horizontal positioning
controls to center the waveform, check for a scope
pattern similar to the one below.
SERVICE NOTE:
L410, L411, L412, L507 and L508
should be tuned to peak the IF pass-
band, and any ripple should be mini-
mized in the passband.
TRANSMITTER ALIGNMENT
RECEIVER ALIGNMENT
Figure 5 - Transmitter/Receiver Tuning & Adjustment Controls
Figure 7 - Test Set-Up, Audio Output Measurement
Figure 6 - Test Set-Up For 20 Hz Double-Trace Sweep Alignment
LBI-31511
LBI-31511
11
Summary of Contents for LBI-31511B
Page 15: ... 19D901350 Sh 1 Rev 10 RECEIVER AUDIO AND SQUELCH WAVEFORM CHECKS LBI 31511 LBI 31511 14 ...
Page 16: ... 19D900977 Sh 1 Rev 20 MECHANICAL LAYOUT LBI 31511 LBI 31511 15 ...
Page 17: ... 19D900977 Sh 2 Rev 14 MECHANICAL LAYOUT LBI 31511 LBI 31511 16 ...
Page 18: ... 19D900980 Sh 1 Rev 4 INTERCONNECTION DIAGRAM LBI 31511 LBI 31511 17 ...
