Vhf Troubleshooting Charts; Troubleshooting Flow Chart For Controller - Motorola Professional Radio Service Manual

VHF Troubleshooting Charts

3.5 VHF Troubleshooting Charts
INT
AUDIO
NO
J403 Audio
at Pin 2 &
Pin 3
YES
Audio from Pin 41
Check Spk.
ASFIC, U404?
Flex Connec-
Check NO
U3220
LV ZIF
EXT
PTT
Radio could
not PTT
externally
OPT_SEL_1 &
OPT_SEL_2
EXT
SPKR
J403 Pin 9 low?
Pin 8 high?
YES
ASFIC U404
Pin 14 & 15
high?
YES
Check
U420 Audio PA
PTT
Press PTT. Red
LED does not
light up
Audio at
YES
AudioPA
(U420)
input
PTT U409
Pin 53
Check
low?
Audio PA
(U420)
YES
NO
Press PTT
Q502-2
NO
High?
Audio at
Check
Pin 2
Q502-2
U404?
voltage
YES
Check
LED should
ASFIC U404
light up
J403
NO
Check
Accessories
Pin 8 & 9
low?
U409
YES
YES
Pin 52, 6
NO
low?
Check
NO
Accessories
Troubleshoot-
NO Check
U404
MCU Check
Power Up
Alert Tone
OK?
NO
Speaker
Check
OK?
PB504
YES
No
U409 EXTAL=
7.3728 MHz?
LED
YES
Q502,R501
OK?
U3701 Pin 19
16.8 MHz
No
Replace
Faulty
Component
5V at U3711?
3.3V at U3201?
Check
MCU
U409 Reset Pin
94 High?
See FGU
ing chart
MCU is OK

Troubleshooting Flow Chart for Controller

YES Not able to pro-
gram RF Board
ICs
NO
NO
Replace
Speaker
YES
YES
NO
Read Radio
OK?
YES
NO
NO
See FGU
Troubleshooting
YES
7.5V at
NO
Pin 3/5 U3711?
7.5V at Pin 1
U3201
YES
YES
NO Check any short
to SWB+,
Vdda or Vddd
YES
3-15
Before replacing
MCU, check SPI
clock, SPI data,
and RF IC select
Check
Setup
Reprogram the
correct data.
NO
Check
Q400
Replace
U3711/U3201