9.1 - 16 TROUBLESHOOTING CHARTS: 450-470MHz
Front-End Tuning Troubleshooting
No
No
Yes
Yes
Did the DC 
change
?
Check 
R5022, R5051, D5011, 
D5012, D5041, D5042
Check R5021, 9.3V DC 
at U0150 pin 14 
before replacing U0150
Send the above Tetra Com 
commands again and  
measure the DC at TP5021
Did the RSSI 
readings change 
at least 5dB
?
Receiver failure!
Go to Receiver Chart
Failure:
PATS parameters FE_FILTER, FE_DAC, FE_OFFSET failed.
Tetra Com Script for RX Test
TEST_ENTER
DELAY 18
Check for "Radio HW is READY"
MODE IDLE
FREQ RX 460.025
L1TIMER ON
AVE 10
MODE RSSI
GO
Use STOP to terminate RSSI reading
Connect the radio's accessory connector to the Tetra Com interface.
Connect the radio's antenna connector to the high power RF output 
on the IFR.
Setup IFR:
Select high power output
No System,
RX Test,
Generator Frequency 460.025MHz,
Generator Level -70dBm,
Duplex Test TX,
Spectrum Analyser
Set Reference Level to 10dBm
Run Tetra Com script for RX Test
Measure RF levels and frequencies with the 50ohms RF probe.
Measure DC levels with a multimeter.
Note the RSSI reading.
Enter "STOP" to terminate RSSI reading
Send Tetra Com command "RXFEFLTR_M"
Note the replied setting.
Send Tetra Com command "RXFEFLTR_M 0"
Send Tetra Com command "RSSI" twice
Note the RSSI reading.
Send Tetra Com command "RXFEFLTR_M 7F"
Send Tetra Com command "RSSI" twice
Note the RSSI reading.
Compare the RSSI readings
Start
6866539D31.book  Page 16  Tuesday, March 20, 2007  6:32 PM