Motorola C139 - Cell Phone - GSM Service Manual - Page 27
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Level 1-2 Service Manual
Troubleshooting Chart
Table 4: Level 1 and 2 Troubleshooting Chart
Symptom
1. Telephone will not turn on or stay on.
2. Telephone exhibits poor reception or
erratic operation such as calls frequently
dropping or weak or distorted audio.
3. Display is erratic, or provides partial
or no display.
4. Incoming call alert transducer audio
distorted or volume is too low.
5. Telephone transmit audio is weak.
(usually indicated by called parties com-
plaining of difficulty in hearing voice).
6. Receive audio from earpiece speaker
is weak or distorted.
Probable Cause
a) Battery either discharged or
defective.
b) Battery terminals open or mis-
aligned.
c) keypad defective.
Connections to or from lower PCB
defective.
LCM defective.
Speaker defective.
Microphone defective.
a) Connections to or from lower
PCB defective.
b) Speaker defective.
July 5, 2005
Verification and Remedy
Measure battery voltage across a 50 ohm (>1
Watt) load. If the battery voltage is <3.25 Vdc,
recharge the battery using the appropriate
battery charger. If the battery will not
recharge, replace the battery. If battery is not
at fault, proceed to b.
Visually inspect the battery terminals on both
the battery and the telephone. Realign and, if
necessary, either replace the battery or refer
to a Level 3 Service Center for the battery
connector replacement. If battery terminals
are not at fault, proceed to c.
Replace the keypad. Temporarily connect a
+3.6 Vdc supply to the battery terminals.
Press and hold the PWR button. If unit turns
on and stays on, disconnect the dc power
source and reassemble with the new keypad.
Check connection between the antenna and
the lower PCB.
Replace the LCM. Verify that the fault has
been cleared and reassemble the unit with
the new LCM.
Replace the speaker as described in the pro-
cedures. Verify that the fault has been
cleared and reassemble the unit with the new
speaker.
Replace the microphone as described in the
procedures. Verify that the fault has been
cleared and reassemble the unit with the new
microphone.
Check connection between the antenna and
the lower PCB. If the connection is OK, pro-
ceed to b.
Temporarily replace the speaker with a
known good speaker. Ensure good connec-
tion. Place a call and verify improvement in
earpiece audio. If fault is cleared, reassemble
the telephone with the good speaker.
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