Motorola GM338

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.