Front-End Tuning - Motorola MTM700 Detailed Service Manual

9.1 - 16
Front-End Tuning Troubleshooting
Failure:
PATS parameters FE_FILTER, FE_DAC, FE_OFFSET failed.
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 405.025MHz,
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.
MTM700 Mobile Radio / Detailed Service Manual
Start
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
Did the RSSI
readings change
at least 5dB
?
No
Send the above Tetra Com
commands again and
measure the DC at TP5021
Did the DC
change
?
No
Check R5021, 9.3V DC
at U0150 pin 14
before replacing U0150
Yes
Receiver failure!
Go to Receiver Chart
Yes
Check
R5022, R5051, D5011,
D5012, D5041, D5042
TROUBLESHOOTING CHARTS (400MHz)
Tetra Com Script for RX Test
TEST_ENTER
DELAY 10
Check for "Radio HW is READY"
MODE IDLE
FREQ RX 405.025
L1TIMER ON
AVE 10
MODE RSSI
GO
Use STOP to terminate RSSI reading
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