Motorola MTM700, Подробное руководство по обслуживанию

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TROUBLESHOOTING CHARTS (400MHz) MTM700 Mobile Radio / Detailed Service Manual 9.1 - 13
LNODCT Troubleshooting
Start
OK
0V DC at U5802
pin 11
?
0V DC at U5803
pin 28
?
IF DC at U5802 pin 37 is not 3V, replace MCM.
Check U5802 pin 45 for 3V DC and pin 3
for 3V DC before replacing U5802.
Check the RF input to
the LNODCT buffer.
IF DC at U5802 pin 37 is not 3V, replace MCM.
Check U5803 pin 8 for 3V DC, pin 40 for 3V DC
and pin 14 for 5V DC before replacing U5803.
RF level
at R5807 about
260mV
?
No Main VCO signal
Go to Main VCO Chart
RF level
at L5805 about
480mV
?
Check transistor stage
Q5801. If TXH is not 5V,
check Q5301
Are
both splitter
outputs measured at
C5803 and C5813
about 200mV
?
Check components between
L5805 and U5801 before
replacing U5801
RF
level at
U5803 pin 24 about
330mV
?
Check components C5814,
R5814
RF level at
L5807 pin 6 and pin 7
about 410mV
?
Is AC
about 750mV p-p
measured with ascope
at U5803 pins
58-61
?
Check U5802 pin 45 for 3V DC
and pin 3 for 3V DC before
replacing U5802
Check U5803 pin 8 for 3V DC, pin 40 for
3V DC, pin 14 for 5V DC and L5807 pins
1,4,8 for 5V DC before replacing U5803
RF level at L5807
pin 2 about
300mV
?
Replace L5807
No
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Failure:
Tetra Com Script for TX Power Test
TEST_ENTER
DELAY 10
Check for "Radio HW is READY"
MODE IDLE
INTR EN
FREQ TX 429.925
L1TIMER ON
TXPOW 6
MODE TXNDC
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.
Run Tetra Com script for TX Power Test
Measure RF levels with the high impedance
RF probe and millivoltmeter.
Measure DC levels with a multimeter.
No or low LNODCT output signal level.
ZWG0130978-O