Motorola GP344 Detailed Service Manual page 355

Introduction
INT
AUDIO
NO
J403 Audio
at Pin 2 &
Pin 3
YES
Audio from Pin 41
Check Spk. Flex
Connection
Check NO
U301
LV ZIF
EXT
PTT
Radio could
not PTT
externally
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
AudioPA
YES
(U420)
input
(U447)
PTT U409
Check
Audio PA
(U420)
YES
NO
ASFIC, U404?
Press PTT
NO
Audio at
Pin 2
Q502-2
U404?
voltage
YES
Check
LED should
ASFIC U404
light up
J403
NO
OPT_SEL_1 &
Check
OPT_SEL_2
Accessories
Pin 8 & 9
low?
U409
YES
Pin 52, 6
NO
low?
Check
NO
Accessories
NO
Check
U404
Figure 3-6 Troubleshooting Chart - Controller
MCU Check
Power Up
Alert Tone
NO
Pin 53
low?
Check
PB504
YES
Q502-2
High?
No
U409 EXTAL=
Check
7.3728 MHz?
LED
YES
Q502,R501
OK?
U201 Pin 19
16.8 MHz
No
Replace
Faulty
Component
5V at U247?
3.3V at U248?
YES
Check
MCU
U409 Reset Pin
94 High?
See FGU
Troubleshooting
chart
MCU is OK
YES Not able to
program RF
OK?
Board ICs
NO
NO
Replace
Speaker
Speaker
OK?
YES
YES
Read Radio
OK?
NO
NO
YES
7.5V at
NO
Pin 3/5 U247?
4/3.3V at Pin 1
U248
YES
NO Check any short
to SWB+,
Vdda or Vddd
YES
2-7
Before replacing
MCU, check SPI
clock, SPI data,
and RF IC select
NO
Check
Setup
YES
Reprogram the
correct data.
See FGU
Troubleshooting
NO
Check
Q400
YES
Replace
U247/U248