Motorola MTM700 Detailed Service Manual page 301

TROUBLESHOOTING CHARTS (800MHz) MTM700 Mobile Radio / Detailed Service Manual
Transmitter Audio Troubleshooting
Tetra Com Script for TX Audio Test
TEST_ENTER
DELAY 10
Check for "Radio HW is READY"
MODE IDLE
GEN_TONE OFF
DSP_LOOP ON
DSP_VOL 0
VOL_M 24
MICGA_M 27
MIC PHF
SPKR INT
Yes
Check stage
U0206-4
Failure:
No audio, low audio level or distortion > 2% at speaker output during
transmitter audio test.
PATS parameters AUD_LBACK_GAIN or AUD_LBACK_DIST failed.
If receiver audio has not been checked, go to Receiver Audio Chart first.
Connect the speaker output on the radio's accessory connector via testbox
RLN4460B to the audio input on the IFR.
Connect the microphone input on the radio's accessory connector via testbox
RLN4460B to the audio output on the IFR.
Setup IFR to:
No System,
AF Test,
AF IN/OUT,
Gen 1 On,
AF 1 Frequency 1kHz
AF 1 Level 80mV
Distortion On
Run Tetra Com script for TX audio test
Measure the 1kHz audio signal with a scope
1kHz signal at
U0201 pin 13
Yes
1kHz signal at
U0201 pin 14
Yes
No
0V DC at
1kHz signal at
U0201 pin 10
U0201 pin 15
?
Yes
No
Check
transistor
Q0201 1kHz signal at
U0206-4 pin 14
Yes
1kHz signal at
FL0200 pin 17
Yes
Replace FL0200
Start
No
Check components and connections
between U0201 pin 13 and accessory
connector pin 2
?
No
9.3V DC
at U0201 pin 11
?
Check
transistor
Q0201
?
No
Check stage
U0206-4
?
No
Before replacing U0203
check R0220, R0225,
C0221 and 3V DC at pin 8
?
Yes
Replace
U0201
?
No
ZWG0130965-O
9.2 - 9