C257/C261 Troubleshooting Chart - Motorola C257 Service Manual

Troubleshooting

C257/C261 Troubleshooting Chart

Table 4: Level 1 and 2 Troubleshooting Chart
Symptom
1. Phone will not turn on or stay on.
2. Phone 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. Phone transmit audio is weak.
(usually indicated by called parties
complaining of difficulty in hearing
voice).
6. Receive audio from earpiece speaker
is weak or distorted.
30
Probable Cause
a) Battery either discharged or
defective.
b) Battery terminals open or
misaligned.
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) Earpiece Speaker defective.
July 1, 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 phone. Realign and, if
necessary, either replace 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 phone
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 phone with
the new LCM.
Replace the speaker as described in the
procedures. Verify that the fault has been
cleared and reassemble the phone with the
new speaker.
Replace the microphone as described in the
procedures. Verify that the fault has been
cleared and reassemble the phone with the
new microphone.
Check connection between the antenna and
the lower PCB. If the connection is OK,
proceed to b.
Temporarily replace the earpiece speaker
with a known good earpiece speaker. Ensure
good connection. Place a call and verify
improvement in earpiece audio. If fault is
cleared, reassemble the phone with the good
earpiece speaker.
C257/C261