Rf Board Back-End - Motorola ASTRO Digital Spectra Plus Service Manual

Troubleshooting Charts
6881076C25-D
Bad SINAD.
Bad 20Db Quieting.
No Recovered Audio.
Note: Inject Modulated On
Carrier Frequency
Signal As Required.
Inject 1 st IF
into Johnson connector
on RF board IF Freqs:
109.65MHz
Check RX Yes
Audio
Front End.
Heard?
No
Check 2nd VCO
"Second VCO Checks"
VCO
Yes
No
Locked?
Before Replacing
U301, Check 2nd
"Second VCO Checks"
5-3
2.1MHz
No
"Display Flashes
Check At
"FAIL 001""
Pin 19
U301?
Yes
Check U301 Voltages,
14.4MHz
No
Programming, &
at ABACUS
14.4MHz VCO
U301 Pin
Components.
15?
Yes
Change
Mode
Activity
Check VOCON
No
On U301
Board.
Sel Pin?
Yes
VCO.
MAEPF-25192-A
Chart C.1 RF Board Back-End
October 28, 2002