TROUBLESHOOTING CHARTS
2-9
MCU Check
Power Up
Alert Tone
OK?
Speaker
OK?
U409 EXTAL=
7.3728 MHz?
U3701 Pin
19 16.8 MHz
5V at
U3711?
3.3V at
U3201?
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
7.5V at
Pin 3/5 U3711?
7.5V at Pin 1
U3201
Check
Q400
Replace
U3711/U3201
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
Check
Accessories
J403
OPT_SEL_1 &
OPT_SEL_2
Pin 8 & 9
low?
Radio could
not PTT
externally
U409
Pin 52, 6
low?
See FGU
Troubleshooting
chart
LED should
light up
Check
MCU
PTT
NO
YES
YES
No
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
J403 Pin 9 low?
Pin 8 high?
ASFIC U404
Pin 14 & 15
high?
Check
Accessories
Check
U404
Check
U420 Audio PA
NO
NO
YES
YES
J403 Audio
at Pin 2 &
Pin 3
Check Spk. Flex
Connection
Audio at
AudioPA
(U420) input
(U447)
Audio from Pin
41 ASFIC, U404?
Check
ASFIC U404
Check
Audio PA
(U420)
Check
U3220
LV ZIF
Audio at
Pin 2
U404?
NO
NO
NO
YES
YES
NO
YES
Figure 2-8
Troubleshooting Chart for Controller
Summary of Contents for GP-688
Page 5: ...Compact Professional Portable Radios Service Maintainability Issue July 2007 ...
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Page 64: ...3 12 CONTROLLER KEYPAD SCHEMATICS ...
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Page 116: ...3 64 PCB and Schematic Drawings IP67 THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 120: ...3 68 PCB and Schematic Drawings IP67 THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 147: ...Compact Professional Portable Radios VHF 136 174MHz Service Information Issue July 2007 ...
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Page 335: ...Compact Professional Portable Radios UHF2 450 527MHz Service Information Issue July 2007 ...
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