Motorola HT Series Service Manual page 89

0DLQWHQDQFH  0+] 7URXEOHVKRRWLQJ &KDUWV
  0+] 7URXEOHVKRRWLQJ &KDUWV
INT
AUDIO
NO
Audio PA (U420)
J403 Audio at
Pin 2 & Pin 3
YES
Audio from Pin 41
Check Spk. Flex
ASFIC, U404?
Connection
Check U351 NO
LV ZIF
Check ASFIC
EXT
PTT
Radio could
not PTT
externally
OPT_SEL_1 &
OPT_SEL_2
Pin 8 & 9
EXT
SPKR
NO
J403 Pin 9 low?
Pin 8 high?
YES
NO
ASFIC U404 Pin 14
& 15 high?
YES
Check
U420 Audio PA
PTT
Press PTT. Red
LED does not light
up
Audio at
YES
input
(U447)
PTT U409 Pin
53
Check
low?
Audio PA
(U420)
YES
NO
Press PTT
Q502-2 High?
NO
Audio at
Check
Pin 2
Q502-2 volt-
U404?
age
YES
LED should
U404
light up
J403
NO
Check
Accessories
low?
U409 YES
YES
Pin 52, 6 low?
Check
NO
Accessories
Troubleshooting
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?
Check MCU
U409 Reset
Pin 94 High?
See FGU
chart
MCU is OK
7URXEOHVKRRWLQJ )ORZ &KDUW IRU &RQWUROOHU
YES
Not able to pro-
gram RF Board
ICs
NO
NO
Replace Speaker
YES
YES
Read Radio OK?
YES
NO
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

Before replacing MCU,
check SPI clock, SPI
data, and RF IC select
NO
Check Setup
Reprogram the
correct data.
See FGU
NO
Check Q400
Replace
U247/U248