Motorola MTM700 Detailed Service Manual page 286

9.1 - 14
Receiver Troubleshooting (Sheet 1)
Failure:
Bit Error Rate @ -114dBm >3.5%
RSSI error >+/- 5dB
PATS parameter GAIN_OFF_L, GAIN_OFF_H and
AGC_SLOPE 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.
Connect the 50ohms RF probe to the low power
RF input on the IFR
Setup IFR:
Select high power output and low power input
No System,
Duplex Test,
Generator Frequency 405.025MHz,
TX Frequency 331.675MHz
Generator Level -30dBm,
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.
10dBm and frequency
Set IFR TX Frequency to 405.025MHz
Set IFR Reference Level to 0dBm
Set IFR TX Frequency
Check components
No
between
U5201 and T5061
Check
D5061, T5062
No
Replace U5201
MTM700 Mobile Radio / Detailed Service Manual
Start
RF
RF
level at
No
level at
TP5071 about
TP5071 about 10dBm
but frequency
stable at
incorrect
331.675MHz
?
Yes
No
RF level at
C5704 about -5dBm
?
Yes
Check transitor
stage Q5701,
switch Q5711 and
switch Q5301
RF level at
No
T5061 pin 4
about -20dBm
?
Yes
4.4V DC at
TP5021
?
to 73.35MHz
Yes
RF level at
RF level at
Q5031 Collector
TP5201 about
about -22dBm
-30dBm
?
?
No
Yes
RF level at 5.8V DC at
Q5031 Collector
TP5202 about
?
-30dBm
?
Yes
Yes
Check components
A between
Q5031 and antenna
connector.
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
Yes
FGU failure!
Go to Main Synthesizer Chart
Yes
No
0V DC at U5701
pin 19 & 20
?
No
Check switch Q5301
and components
between Q5301 and
U5701 pin 19 & 20
No
Before replacing U0150
check R5021 and 9.3V
DC at U0150 pin 15
Yes
Check components
between
Q5031 and T5061
Before replacing Q5031
No
check: 9.3V DC at C5002,
0V DC at C5001.
Check Q5001 and
associated components.
TROUBLESHOOTING CHARTS (400MHz)
No
RF level at
No VCO output signal!
TP5702 about
Go to Main VCO Chart
-5dBm
?
Yes
Replace U5701
ZWG0130968-O
ZWG0130968-O
Receiver Chart 1
UHF