Rx If-Poor Sinad Or No Audio (700-800 Mhz); Figure 5-37. Rx If-Poor Sinad Or No Audio (700-800 Mhz) - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

Troubleshooting Charts: Flowcharts
5.6.35 RX IF—Poor SINAD or No Audio (700–800 MHz)
Measure the IF
signal level
(73.35MHz)
at TP6252
Level
is +4dB
referenced to the
RF input
level?
Yes
Measure the IF
signal level
(73.35MHz)
at TP6350
Level
is +20dB
relative to the RF
input level?
Yes
Refer to
troubleshooting
flow digram for
Receiver Back End
Figure 5-37. RX IF—Poor SINAD or No Audio (700–800 MHz)
6881096C74-B
No
troubleshooting
flow diagram for
Receiver Front End
Measure the DC
No
Bias voltage level
on transistor
>~5.0V at Q6350
0.7V at Q6350
Inspect crystals and
matching networks for
missing components
and/or soldering defects
Refer to
Q6350
Voltage
level of
No
Collector
(pin 3)?
Yes
Voltage
level of
No
Base
(pin 1)?
Yes
Inspect biasing
components and
check Voltage
Regulator U0950 for
normal operation
Replace
Q6350
MAEPF-27809-O
May 25, 2005
5-49