Troubleshooting Charts; Troubleshooting Flow Chart For Controller - Motorola GP88s Service Manual

Troubleshooting charts

10.0 Troubleshooting charts
INT
AUDIO
NO
J402 Audio
at Pin 3 &
Pin 4
YES
Audio from Pin 41
Check Spk. Flex
ASFIC, U404?
Connection
Check NO
U301
LV ZIF
EXT
PTT
Radio could
YES
not PTT
externally
EXT
SPKR
J402 Pin 3 low?
Pin 4 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
Audio PA
(U420) input
(U447)
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
U409 YES
Check
Pin 52 & 6
MCU
low?
NO
See FGU
Troubleshoot-
ing chart
NO
Check
Accessories
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?
U201 Pin 19
16.8 MHz
No
Replace
Faulty
Component
5V at U247?
3.3V at U248?
U409 Reset Pin
94 High?
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
See FGU
NO
Troubleshooting
YES
7.5V at
NO
Pin 3/5 U247?
4/3.3V at Pin 1
U248
YES
YES
NO Check any short
to SWB+,
Vdda or Vddd
YES
9A-51
Before replacing
MCU, check SPI
clock, SPI data,
and RF IC select
Check
Setup
Reprogram the
correct data.
chart
NO
Check
Q400
Replace
U247/U248