Motorola MTM700

9.1 - 8 MTM700 Mobile Radio / Detailed Service Manual TROUBLESHOOTING CHARTS (400MHz)
Receiver Audio Troubleshooting
Tetra Com Script for RX Audio Test
MODE IDLE
DSP_LOOP OFF
GEN_TONE 1000
DSP_VOL -5
VOL_M 27
SPKR INT
Yes
Failure:
No audio or low audio level at speaker output or handset audio output.
High distortion at speaker output or handset audio output.
PATS parameters AUD_LBACK_GAIN or AUD_LBACK_DIST failed.
Start
1kHz signal
at U0201 pin 4
?
Yes
No
No
1kHz signal
at FL0200 pin 2
?
0V DC
at U0201 pin 9
?
No
Connect the speaker output on the radio's
accessory connector via testbox RLN4460B to the
audio input on the IFR.
Setup IFR to:
No System,
AF Test,
AF IN/OUT,
Gen 1,2,3 Off,
Distortion On
Run Tetra Com script for RX audio test
Measure the 1kHz audio signal with a scope
No
Before replacing
FL0200 check for
activity on pin 7,8,11,13
1kHz signal
at U0201 pin 5
?
If no 1kHz signal at
accessory connector pin
11, check stage U0206-1
Before replacing U0204
check resistors R0221,
R0228 and 3V DC at pin 8
Check
transistor
Q0203
Yes
9.3V DC
at U0201 pin 16
No
9.3V DC supply failure!
Go to DC Supply Chart
Replace
U0201
Yes
If no 1kHz signal at
handset audio output,
check stage U0206-2
0V DC at
U0205 pin 8
?
Yes
No
Check transistor Q0200
and connected resistors
If no 1kHz signal at
speaker output, check
R0244, R0245, C0227,
13.2V at pin 7 before
replacing U0205.
?
TEST_ENTER
DELAY 10
Check for "Radio HW is READY"
ZWG0130957-O