No Tx Audio (380-470 Mhz And 450-520 Mhz); Figure 5-25. No Tx Audio (380-470 Mhz And 450-520 Mhz) - Motorola ASTRO XTL 1500 Detailed Service Manual

5-34
5.6.23 No TX Audio (380–470 MHz and 450–520 MHz)
START
No TX Audio
Inject a 2.0Vpp
1kHz tone into Mic
input and key radio
1.0Vpp
at R5755 or
TP5792?
0.4Vpp
at
C5780?
Check
synthesizer
loop filter
components
Figure 5-25. No TX Audio (380–470 MHz and 450–520 MHz)
June 15, 2005
This Flow chart only checks the modulation
path of the FGU. Readings are typical and
can vary with deviation settings that are
programmed during tuning.
No
Yes
Check deviation
No
tuning or replace
Yes
NOTE: After the modulated signal is coupled
through C5780 the signal is attenuated to levels
below 2mv making a measurement difficult for
most oscilloscopes.
Troubleshooting Charts: Flowcharts
GOTO
Controller
Section
U5752
6815854H01-A