Motorola GM338

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 MHz
TP0866
= 0V
NO
Check / Replace
R0873 / U0873 /
U0871
Check / Replace
R0866 / C0866 /
Q0866 / R0863
Check / Replace
R0861 / R0862 / D0861
C0861 / C0862 / U0861
C0863 / C0864 / C0865
NO
YES
YES
A