5-18
Troubleshooting Charts
September 5, 2008
6881076C25-E
Chart C.24 VHF Receiver Front-End Hybrid
START
Measure Transceiver
Sinad by Injecting
at J9127
Signal
Sinad
<-120 with Preamp
?
Yes
No
No
No
No
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
No Problem with
RX Front End or
RF Board
Measure Sinad
Inject 106.5 MHz
into RF Board
at J350
Sinad
<- 120
?
Troubleshoot
RF Board
Check DC
Voltage at IF
Output Pad
9.6V
?
Troubleshoot
DC Feed from
RF Board
~
_
Check Biasing
on Q3202:
Vcollector ~
_ 7.5V
Vbase
?
Check Bias Circuit
and Associated
Components
Check Module Gain: Inject
Measure RF Level
at Input of 1st
Check Inject Level
at Injection Input Pad
Troubleshoot
RF Injection or
Carrier Board
+ 20dBm
?
>
_
160MHz -20dBm at J9127
Measure at IF Output
Is
<-117 non-
Preamp
Is
Voltage
~
_ 0.9 to 1.6V
Is
Voltage At
Q3202 OK
Is
>-13 with
Preamp; >-22 Non-
Preamp
?
Recheck RF Board and
Transceiver Sinad
Mixer
Is
>-7dBm with
Preamp; >-17 dBm
Non-Preamp
?
Check the Preselector
and its Components
Replace as Necessary
Is
Level
Check 1st Mixer and
Associated Components
Replace as Necessary
Содержание ASTRO Digital Spectra
Страница 1: ...ASTRO Digital Spectra and Digital Spectra Plus UHF VHF 800 MHz Mobile Radios Detailed Service Manual ...
Страница 2: ......
Страница 6: ...September 5 2008 6881076C25 E iv Document History Notes ...
Страница 20: ...xviii List of Tables September 5 2008 6881076C25 E Notes ...
Страница 24: ...September 5 2008 6881076C25 E xxii CommercialWarranty Notes ...
Страница 48: ...September 5 2008 6881076C25 E xlvi Model Numbering Charts and Specifications Notes ...
Страница 142: ...September 5 2008 6881076C25 E 3 82 Theory of Operation Power Amplifiers Notes ...
Страница 218: ...September 5 2008 6881076C25 E 4 76 Troubleshooting Procedures Power Amplifier Procedures Notes ...
Страница 258: ...September 5 2008 6881076C25 E 6 14 Troubleshooting Waveforms ASTRO Digital Spectra Plus VOCON Board Waveforms Notes ...
Страница 434: ...September 5 2008 6881076C25 E Glossary 10 Notes ...
Страница 440: ...Index 6 September 5 2008 6881076C25 E Notes ...
Страница 441: ......