Receiver - Motorola MTM700 Detailed Service Manual

9.2 - 14
Receiver Troubleshooting (Sheet 1)
Failure:
Bit Error Rate @ -114dBm >3.5%
RSSI error > ±5dB
Inspect RF input path. Input a strong RF
signal of about -40dBm at 860.525 MHz at
the RF connector and check signal at Pin4
of the Mixer U5002.
Is the signal
present?
Is Pin 1 of the
Mixer U5002 at
3.3 Volts?.
Is the LO present at pin
3 of U5002?
MTM700 Mobile Radio / Detailed Service Manual TROUBLESHOOTING CHARTS (800MHz)
NO
Find and repair component or soldering problem in input path.
Check LNA U5002 which should give about 17dB of gain. Make
sure that U5002 pin 3 is at 1.9V. Replace LNA if necessary.
Also check FL5002, C5022, L5008, and C5027.
YES
NO
YES
NO
YES
NO
Is there 3.3VDC at
C5031?
YES
NO
Is the LO present at
C5038?
YES
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
Check U5001 -
Pin 5 should be at 3.3V.
Check R5007 & L5004.
GO to Synthesizer and
VCO Troubleshooting Chart.
Check L5013, L5014,
L5017, C5028.
GO to Receiver IF
Troubleshooting Chart.