Troubleshooting Flow Chart For Controller (Sheet 2 Of 2) - Motorola Professional Radio Service Manual

3-36
MCU Check.
Power Up
Not able to pro-
YES
Alert Tone
gram RF Board
OK?
ICs.
NO
NO
Replace Speaker.
Speaker
OK?
YES
YES
U409 EXTAL=
Read Radio OK?
7.3728 MHz?
NO
NO
U201 Pin 19
16.8 MHz.
YES
7.5V at
NO
5V at U202? Pin 3/5 U202?
3.3V at U203? 4/3.3V at Pin 1
U203.
YES
Check any short to
NO
U409 Reset
SWB+,
Pin 94 High?
Vdda or Vddd.
YES
MCU is OK.

Troubleshooting Flow Chart for Controller (Sheet 2 of 2)

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
U202/U203.
900 MHz Troubleshooting Charts