TROUBLESHOOTING CHARTS (800MHz) MTM700 Mobile Radio / Detailed Service Manual 9.2 - 15
Receiver Troubleshooting (Sheet 2)
Does the
radio receive?
Repeat Receiver Troubleshooting if radio still
does not receive.
NO
YES
NO
YES
Are Bias volt-
ages correct?
Is Sampling Clock @
18MHz present at
C5197?
NO
YES
Measure Bias Voltages on IF amplifier Q5201
(5.1V at collector and 0.9V at base).
ABACUS Troubleshooting Chart
Check R5209, R5208,
R5207, R5205.
Check that transistor Q5190 Bias voltages are approx-
imately: Base 3.8V, Collector 4.7, and emitter 3.2V.
Voltage at R5196 should be about 1.5V.
YES
Is the second IF @
71.1MHz present
@ C5186?
NO
Check for correct component placement in
the 18MHz section.
Check transistor Q5180 Bias voltages:
Base 2.8V, Collector 4.7, and emitter 2.2V.
Voltage at R5186 should be about 1.1V.
Check for correct component placement in
the second IF section.
Make sure that 5V_FN is present at C5139 and 3.3V
at pin5 U5102 and U5103.
If 5V_FN is not present at C5139, change U5101.
ABACUS section can be checked by spraying an
IF signal at 73.35MHz into the IF section or apply-
ing directly to C5125.
Tetra Com Script for Rx Test:
TEST_ENTER
DELAY 10
Check for "Radio HW is READY"
MODE IDLE
FREQ RX 860.525
L1TIMER ON
AVE 10
MODE RSSI
GO
Use STOP to terminate RSSI reading
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