Motorola P7689, Service Manual, Page: 44 / 59

of 59 GSM Field Service Support 44
P7689 / P7789
and re-assemble the unit with the new PCB.
5. Personal telephone transmit
audio is weak, (usually indicated by
called parties complaining of
difficulty in hearing voice from
personal phone).
a) Microphone connections to
The main RF / Logic board are
defective. 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.
b) Microphone defective 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 portable with new Microphone. If
Microphone is not at fault, re-install original
Microphone and proceed to c.
c) Logic/RF Board Assembly
defective. 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.
6. Personal telephone receive audio
is weak and/or distorted. (From
speaker)
a) Connections to/from speaker
and Logic/RF Circuit board
defective. Gain access to Logic/RF board as described in the
DISASSEMBLY instructions in this manual. Check
pads on the Logic/RF circuit board. Clean pads if
necessary. If pad is at fault proceed to d. If
connection is not at fault, Proceed to b.
b) Earpiece Speaker defective. Remove speaker from front housing and insert
known good speaker. Place a call and verify
improvement in earpiece audio. If better, reassemble
the phone with the good speaker. If it was no better
then proceed to c.
c) Antenna assembly is
defective. 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 assembly then
proceed to d.
d) Logic/RF Board Assembly
Defective. d) Replace Logic/RF Assembly (refer to symptom
1c). Verify that the fault has been cleared and
Re-assemble the unit with the new PCB.
7. Personal telephone will not
recognize/accept SIM card
a) SIM card defective Initially check that the contacts on the card are not
dirty. Clean if necessary, and check if fault has been
eliminated. If the contacts are clean, insert a
Known good SIM card into the portable telephone.
Power up the unit and confirm whether or not the
card has been accepted. If the fault no longer
Exists, the defective SIM card should be replaced. If
the SIM card is not at fault, proceed to b.
b) Logic/RF Board Assembly
Defective. 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.
8. Phone does not sense when flip is
Opened or closed (L7789 Only)
(usually indicated by inability to
answer incoming calls by opening
the flip, or inability to make
outgoing calls).
a) Magnet in flip defective Replace Front / flip assembly with known good one,
refer to the DISASSEMBLY instructions in this
manual. Place call to portable phone and verify
ability to answer by opening flip. If faulty rebuild
phone with new front / flip Assy. If fault is still
present, replace original front/flip assembly and
proceed to b.
SYMPTOM PROBABLE CAUSE VERIFICATION AND REMEDY
b) Logic/RF Board Assembly
Defective. 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.
9. Internal Charger not working a) Faulty charger circuit on main
Board. Test a selection of batteries in the rear
pocket of the desktop charger.
Check LED display for the charging
indications. If these are charging ok,
then the internal charger is at fault.
Replace Logic/RF Board Assembly