Motorola MTM700

9.1 - 10 MTM700 Mobile Radio / Detailed Service Manual TROUBLESHOOTING CHARTS (400MHz)
Warping Failure Troubleshooting
OK
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
RF
power at
antenna connector
> 10dBm
?
RF
level at
TP5401 about
-30 dBm
?
No TX Output Power!
Go to RF Power Amplifier Chart.
No LNODCT Output Power!
Go to LNODCT Chart.
FGU failure!
Go to Main Synthesizer Chart.
Is frequency
stable at 429.925MHz
+/-7kHz
?
Send Tetra Com
command "PN 0"
Is frequency
about 7kHz above
429.925MHz
?
DC
at Y5362 pin 1 about
2.4V
?
Check R5361 before
replacing U5331
Send Tetra Com
command "PN 1FF"
Check for 3V DC at
Y5362 pin 4 before
replacing Y5362
Is frequency
about 7kHz below
429.925MHz
?
DC
at Y5362 pin 1 about
0.4V
?
Replace U5331
Replace Y5362
Failure:
PATS parameters WARP_RANGE, WARP_RES, FREQ_ERR or
WARP_SP failed
Tetra Com Script for TX FGU Test
TEST_ENTER
DELAY 10
Check for "Radio HW is READY"
MODE IDLE
INTR DIS
FREQ TX 429.925
L1TIMER ON
TX POW 4
RFTON ATT 0.5
RFTON FRQ 0
RFTON CHN I
FEEDBACK OPEN
MODE RFTONE
Use MODE IDLE to terminate transmit mode
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 50 ohms RF probe to the low power RF input on the IFR.
Setup IFR:
Select high power input for measuring power at the antenna connector.
Select low power input for measuring with 50ohms RF probe.
No System,
TX Test,
TX Frequency 429.925MHz
Spectrum Analyser
Set Reference Level to 30dBm.
Run Tetra Com script for TX FGU Test.
Measure RF levels and frequencies with the 50ohms RF probe.
Measure DC levels with a multimeter.
If the cover is removed from the chassis, the RF PA is disabled to
prevent overheating of the FET devices. To measure the power at the
antenna connector, the pressure pad can be used to short the contact
area on the main board. This should be done only for a few seconds.
Start
ZWG0130971-O