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Internal audio failures
speaker doesn't work
(receiving audio)
microphone doesn't
work
change N200
COBBA
version 1.0 / 05.11.1999
CONFIDENTIAL
Internal audio failure
check connection
between L202, L203
Yes
to earphone pads
(0 Ohm)
OK
check the mechanic
and
impedance of
speaker
(about 30 Ohm)
check contacts and
impedance of
Yes
microphone (800
Ohm)
Ok
check the
microphone bias
voltage 1,7V on C242
(audio loop enable)
Ok
Check audio signal
on C258, C259
Ok
Check 2,8V DC VBB
on C117 and 2,8V
DC VCOBBA on
C148
Ok
check COBBACLK
13MHz 3,2Vpp on
OK
J201and
COBBARESET on
J343 during
initialisation
not OK
change L202 or L203
not OK
change speaker
not OK
change microphone
check voltage on
not OK
R214
follow signal back to
not OK
the microphone
Check function of
not OK
CCONT
swap the phone
not
because MAD or
PCB should be the
OK
reason
Service & Analysis Center Europe
Training Team
check the
resistance between
not OK
the lines and
gruond
>1MOhm
check the
not OK
connection
X503-->PCB for
soiled
not OK
change N200
COBBA
Page 21 of 37
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