Motorola ASTRO Digital XTL 5000

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