Motorola T189 Service Manual page 35

SYMPTOM
4. Incoming call alert transducer
audio, distorted or volume is too
low.
5. Personal telephone transmit audio
is weak, (usually indicated by called
parties complaining of difficulty in
hearing voice from personal phone).
6. Personal telephone receive audio
is weak and/or distorted. (From
speaker)
PROBABLE CAUSE
a) Faulty alert Transducer
b)Main RF / Logic PCB
defective
a) Microphone connections
to
the main RF / Logic board are
defective.
b) Microphone defective
b) Logic/RF Board
Assembly
defective.
Dirty Contacts / Misalignment
of contacts or faulty speaker.
c) Antenna assembly is
defective.
d) Logic/RF Board
Assembly
Defective.
VERIFICATION AND REMEDY
Replace Alert Transducer from rear
housing refer to
disassembly procedure.If not Alert then
proceed to b)
Replace Logic/RF Board Assembly (refer
to
symptom 1c). Verify that the fault has
been cleared
and re-assemble the unit with the new
PCB.
Gain access to the Microphone as
described in the
DISASSEMBLY instructions in this
manual. . Check
connections. If connector is faulty proceed
to c if the
connector is OK, proceed to b.
Gain access to microphone .Disconnect
and
substitute a known good Microphone.
Place a call
and verify as heard by called party. If
good, re-assemble
unit with new Microphone. If Microphone
is not at fault, re-install original
Microphone and
proceed to c.
Replace Logic/RF Board Assembly (refer
to
symptom 1c). Verify that the fault has
been cleared
and re-assemble the unit with the new
PCB.
Ensure pads on PCB are clean and that
speaker
contacs are sat almost vertical to each
other. If Ok
replace with known good speaker and
check for call
quality. If still poor proceed to c)
Attempt a re-phasing of the unit and
recheck the
symptom. If symptom is the same but unit
re-phases
correctly, check to make sure the antenna
connector
is correctly soldered to the main board and
that the
antenna is fitted correctly. If ok, substitute
a known
good antenna assembly. If this does not
cure the
fault, re-install the original antenna then
proceed to
d).
d) Replace Logic/RF Assembly (refer to
symptom