3-8
UHF Troubleshooting Charts
3.9
UHF Troubleshooting Charts
Troubleshooting Flow Chart for Controller
MCU Check
Power Up
Alert Tone
OK?
Speaker
OK?
U409 EXTAL=
7.3728 MHz?
U201 Pin 19
16.8 MHz
5V at U247?
3.3V at U248?
U409 Reset Pin
94 High?
MCU is OK
Not able to pro-
gram RF Board
ICs
Before replacing
MCU, check SPI
clock, SPI data,
and RF IC select
Replace
Speaker
Read Radio
OK?
Check
Setup
Reprogram the
correct data.
See FGU
Troubleshooting
chart
7.5V at
Pin 3/5 U247?
4/3.3V at Pin 1
U248
Check
Q400
Replace
U247/U248
Check any short
to SWB+,
Vdda or Vddd
Press PTT. Red
LED does not
light up
PTT U409
Pin 53
low?
Press PTT
Q502-2
High?
Check
PB504
Check
Q502-2
voltage
LED
Q502,R501
OK?
Replace
Faulty
Component
Radio could
not PTT
externally
U409
Pin 52 & 6
low?
See FGU
Troubleshoot-
ing chart
LED should
light up
Check
MCU
PTT
NO
YES
YES
No
No
YES
YES
NO
YES
YES
NO
NO
YES
YES
NO
NO
YES
NO
YES
NO
YES
YES
NO
NO
YES
EXT
SPKR
EXT
PTT
INT
AUDIO
J402 Pin 3 low?
Pin 4 high?
ASFIC U404
Pin 14 & 15
high?
Check
Accessories
Check
U404
Check
U420 Audio PA
NO
NO
YES
YES
J402 Audio
at Pin 3 &
Pin 4
Check Spk. Flex
Connection
Audio at
AudioPA
(U420)
input
Audio from Pin 41
ASFIC, U404?
Check
ASFIC U404
Check
Audio PA
(U420)
Check
U301
LV ZIF
Audio at
Pin 2
U404?
NO
NO
NO
YES
YES
NO
YES