Part 2 Of 3; Figure 5-20. Rx Back-End-Poor Sinad Or No Audio (380-470 Mhz And 450-520 Mhz); Figure 5-21. Rx Back-End-Poor Sinad Or No Audio (380-470 Mhz And 450-520 Mhz); Figure 5-22. Rx Back-End-Poor Sinad Or No Audio (380-470 Mhz And 450-520 Mhz) - Motorola ASTRO XTL 1500 Detailed Service Manual

5-30
5.6.19 RX Back-End—Poor SINAD or No Audio (380–470 MHz and 450–520 MHz)—

Part 2 of 3

Measure
control voltage
at R5013
Freq 2nd LO
VCO <107.4
Freq 2nd LO
VCO <107.4
Figure 5-21. RX Back-End—Poor SINAD or No Audio (380–470 MHz and 450–520 MHz)—Part 2 of 3
June 15, 2005
1
No
MHz?
Yes
No
MHz?
Yes
Inspect 2nd LO VCO
for missing parts or
varactor diode
R5013 NOMINAL
VOLTS DC FREQ (MHz)
0.0
1.6
4.0
5.0
No
R5013
= 5.0V?
Yes
No
R5013 = 0.0V?
Yes
solder defect
Visual
No
inspection
OK?
Yes
Replace
D6051
Troubleshooting Charts: Flowcharts
68.0
71.1
75.6
77.0
3
3
Repair defects
and/or replace
suspect parts
6815854H01-A