No Tx Audio (700-800 Mhz); Figure 5-41. No Tx Audio (700-800 Mhz) - Motorola ASTRO XTL 1500 Detailed Service Manual

5-52
5.6.41 No TX Audio (700–800 MHz)
START
No TX Audio
Inject a 2.0Vpp
1kHz tone into Mic
input and key radio
1.0Vpp
at R6782 or
VN_T67770?
0.4Vpp
at TP6755 or
C6783?
Check
synthesizer
loop filter
components
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 C6783 the signal is attenuated to levels
below 2mv making a measurement difficult for
most oscilloscopes.
Figure 5-41. No TX Audio (700–800 MHz)
Troubleshooting Charts: Flowcharts
GOTO
Controller
Section
U6751
MAEPF-27814-O
6815854H01-A