Motorola Gm328 Gm338 Gm398 Detailed 6804112j18 E Manual

Controlhead GM338 Troubleshooting Flow Chart 3-5
2.3 Display
Power Up Alert Tone is OK, volume knob does operate,
indicator/backlight is on but nothing on display
YES
NO
YES
NO
V5 (against 5V)
TP0973 between
-6V and -7V ?
Activity on
Address & Data lines
A0 / D0..D7 / CS1
of U0971?Check for shortage
U0831 / U0971
Check LCD Assembly
Check / Replace
C0971 / C0973 / R0972
R0973 / R0974 / U0971 

3-6 Controlhead GM338 Troubleshooting Flow Chart
2.4 Backlight
Power Up Alert Tone is OK, volume knob does operate,
indicator/display is on but no backlight
NO
YES
YES
NO U0831 Pin 58
is toggling ?
Base of 
Q0934
> 0.7V ?Check / Replace 
R0847 / C0843 / R0943
Check for shortage
U0831
YES
NO Collector of
Q0934
>5V and < 11V ?Check / ReplaceQ0934 U0931 /R0941 / 
R0942 / R0944 / R0945
Check / Replace
Q0933 / R0947 / R0948 

Controlhead GM398 Troubleshooting Flow Chart 3-7
3.0 Controlhead GM398 Troubleshooting Flow Chart
3.1 On/Off 
R0854
Pin TAB1
when pressed
=5V ?
J0801 PIN2
> 10V ?
J0801 PIN2
 =5V?
Check / Replace
Q0853 / R0853
YES
NO
YES
NO
YES
NOCheck / Replace
D0852 / R0852
Check / Replace
Volume Pot R0854
Check / Replace
Q0851
Radio can not be switched on via ON/OFF/Volume Knob
YES
R0854
Pin TAB
= 5V?NOCheck / Replace
R0855 / VR0855 / D0855
C0856
Press and hold
On/Off/
Volume Knob 

3-8 Controlhead GM398 Troubleshooting Flow Chart
3.2 Microprocessor 
Power Up Alert Tone is audible on external speaker but volume
knob does not operate and no indicators are on
TP0876
=5V ?
NO YES
U0871
Pin 73 EXTAL
= 8 MHzTP0866
= 0V NO
Check / Replace
R0873 / U0873 /
U0871Check / Replace
R0866 / C0866 / 
Q0866 / R0863
Check / Replace
R0861 / R0862 / D0861
C0861 / C0862 / U0861
C0863 / C0864 / C0865
NO
YESYES
A 

Controlhead GM398 Troubleshooting Flow Chart 3-9
3.3 Microprocessor (cont.)
Data Signal
on J0801
Pin 5 BUS+
?
Data Signal
on TP0877
SCI_RX
?
Data Signal
on TP0878
SCI_TX
 ?
Check / Replace
D0872 / R0887
YES
YES
YES
NO
NO
NOCheck / Replace
U0871
Check 
Radio Controller
Check / Replace
R0888 / R0889
Measure with scope
while rotating
Volume Pot
A 

3-10 Controlhead GM398 Troubleshooting Flow Chart
3.4 Display 
TP0973
Voltage Sense
between
 2V and 2.4V
?
Activity on
Address & Data lines
A0 / D0...D7 / CS1
of U0971
?
NO
YES
YES
NO
Check / Replace
Flex connection
Resistors on Address & Data
lines and LCD Module
Check / Replace 
LCD Module
Check for shortage
U0871
Power Up Alert Tone is audible, volume knob does operate,
indicator/backlight is on but nothing is seen on the display. 

Controlhead GM398 Troubleshooting Flow Chart 3-11
3.5 Keypad Backlight 
U0871 Pin 25
is toggling ?
Base of Q0943
> 0.7V ?
Collector of
Q0943
>5V & < 11V
 ?
Check / Replace
Q0941 / R0955 / R0957
YES
YES
YES
NO
NO
NO
Check / Replace
Q0943 / U0941 / R0941
R0943 / R0949 / R0951
Check for shortage 
U0871
Check / Replace
R0945 / C0943 / R0947
Power Up Alert Tone is audible, volume knob does operate,
display is on but no keypad backlight. 

3-12 Controlhead GM398 Troubleshooting Flow Chart
3.6 Display Backlight 
U0871 Pin 24
is toggling ?
Base of Q0963
> 0.7V ?
Collector of
Q0963
>5V & < 11V
 ?
Check / Replace
Q0961 / R0975 / R0977
YES
YES
YES
NO
NO
NO
Check / Replace
Q0963 / U0941 / R0961
R0963 / R0969 / R0971
Check for shortage 
U0871
Check / Replace
R0965 / C0963 / R0967
Power Up Alert Tone is audible, volume knob does operate,
display is on but no display backlight. 

4-1
Section 4
CONTROLHEAD PCBS / SCHEMATICS / PARTS LISTS
1.0 Allocation of Schematics and Circuit Boards
.Table 4-1   Controlhead Diagrams and Parts Lists
PCB :
Controlhead GM328
8486146B07 Main Board Top Side
8486146B07 Main Board Bottom SidePage 4-3
Page 4-3
SCHEMATICS
Sheet 1 of 2
Sheet 2 of 2
Page 4-4
Page 4-5
Parts List
8486146B07 Page 4-6
Table 4-2   Controlhead Diagrams and Parts Lists
PCB :
Controlhead GM338
8486155B06 Main Board Top Side
8486155B06 Main Board Bottom SidePage 4-7
Page 4-7...

4-2Allocation of Schematics and Circuit Boards
THIS PAGE INTENTIONALLY LEFT BLANK