Troubleshooting Charts
5-3
6881076C25-E
September 5, 2008
Chart C.1 RF Board Back-End
Bad SINAD.
Bad 20Db Quieting.
No Recovered Audio.
Inject 1st IF
into Johnson connector
on RF board IF Freqs:
109.65MHz
Note: Inject Modulated On
Carrier Frequency
Signal As Required.
Change
Mode
Before Replacing
U301, Check 2nd
VCO.
"Second VCO Checks"
Check RX
Front End.
Check 2nd VCO
"Second VCO Checks"
Audio
Heard?
VCO
Locked?
2.1MHz
Check At
Pin 19
U301?
No
No
Yes
Yes
Yes
"Display Flashes
"FAIL 001""
No
14.4MHz
at ABACUS
U301 Pin
15?
Check U301 Voltages,
Programming, &
14.4MHz VCO
Components.
No
Yes
Activity
On U301
Sel Pin?
Check VOCON
Board.
No
Yes
MAEPF-25192-A
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: ......