Fail To Call - Blu Dash 4.5 Service Manual

3.4 Fail to call

When call with somebody, we cannot hear what he says or he cannot hear what we say:
This fail may cause by receiver or microphone fail, it can test in factory mode,
type"*#*#9375#*#*" enter factory mode, Transmitter/Receiver test, if ok, it may RF fail, if fail,
we need to make sure is receiver or microphone fail.
Call 112, if can hear voice, it may microphone problem, check microphone related
circuit ,check R801, R802, R808, R809 and T801，T802 solder ok or not, if all ok, change a
new microphone, also fail, check CPU, re-hot or change a new one.
Call 112, if cannot hear voice, it may receiver problem, change a new receiver, check R812,
R813 and C817，C818 ok or not, if ok, check CPU, re-hot or change a new one.
Change a
new one
Rework
uncorrected
component
Hot or change
new one
Voice sending or receiving no
function
MIC
Y
Change
new MIC
N
N
Check
Related
R C TVS?
Y
N
Check
U300?
Can hear sound in
Factory mode?
N
Check
Receiver or
MIC
problem？
Check
U300?
Y
Check RF
Receiver
Y
Check
Change
new one
new
REC
N
N
Check
Related
R, C, TVS?
Y
Y
N
a
Rework
uncorrected
component
Hot or change
new one