LOGO EV730, Service Manual, Page: 27 / 44

27
No Ringtone
Quit vibration
or mute mode.
Turn on ringtone and test LS401
with oscillograph, there should be
audio signal.
No Ringtone
Remove receiver and test
by the “buzzer” of
multi-meter to hear if there
is any sound.
NO
NO
NO
YES
YES
YES
YES
Replace the
component.
Check if the phone is
set to vibration or mute
mode.
Check if the volume is
set to lowest.
Turn up the volume
Replace U101 or U401
NO
*#84666*#, option 7,
test if the ringtone is
normal.
NO