Rx Back-End-Poor Sinad Or No Audio (136-174 Mhz)-Part 3 Of 3 - Motorola ASTRO Digital XTL 5000 Detailed Service Manual

5-20
5.6.6 RX Back-End—Poor SINAD or No Audio (136–174 MHz)—Part 3 of 3
Inspect solder on U3000
and supporting circuitry,
look for missing or
misplaced components
Freq.
CLKOUT at
1.2MHz
Replace
U3000
Figure 5-10. RX Back-End—Poor SINAD or No Audio (136–174 MHz)—Part 3 of 3
May 25, 2005
2
Measure DC
tuning voltage
at R3010
Freq of
o
CLKOUT
<1.2MHz?
Yes
DC
o
voltage at
R3010 =
3.0V?
Yes
3
Repair defects
o
and/or replace
suspect components
?
Yes
DC
o
voltage at
R3010 =
0.0V?
Yes
3
Inspect clock oscillator
circuit for solder defects
and/or missing components
Visual
o
inspection
OK?
Yes
o
Problem
Found
Troubleshooting Charts: Flowcharts
3
Repair defects
and/or replace
suspect components
MAEPF-27808-O_VHF
6881096C74-B