Motorola GM338

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
NO
Check / Replace
U0871
Check
Radio Controller
Check / Replace
R0888 / R0889
Measure with scope
while rotating
Volume Pot
A