Troubleshooting - Motorola A920 Service Manual

Troubleshooting

Troubleshooting
Table 7. 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
complaining of difficulty in hearing
voice).
6. Receive audio from earpiece speaker
is weak or distorted.
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Probable Cause
a) Battery either discharged or
defective.
b) Battery terminals open or
misaligned.
c) Transceiver board defective.
a) Antenna defective.
b) Transceiver board defective.
a) Mating connections to or from
transceiver board faulty.
b) Transceiver board defective.
Faulty transceiver board.
a) Microphone defective.
b) Transceiver board defective.
a) Connections to or from
transceiver board defective.
October 27, 2003
Verification and Remedy
Measure battery voltage across a 50 ohm (>1
Watt) load. If it is <3.25 Vdc, recharge the
battery using the appropriate charger. If it will
not recharge, replace the battery. If battery is
not at fault, proceed to b.
Visually inspect battery terminals on both
battery and phone. Realign and, if necessary,
either replace the battery or refer to a Level 3
Service Center for battery connector
replacement. If battery terminals are not at
fault, proceed to c.
Remove transceiver board assembly.
Substitute a known good transceiver board
and temporarily reassemble the phone. Press
the PWR button; if phone turns on and stays
on, disconnect the dc power source and
reassemble phone with new transceiver
board. Verify that the fault has been cleared.
Check connection between antenna and
transceiver board. If the connection is OK,
substitute a known good antenna. If the fault
is still present, proceed to b.
Replace transceiver board (refer to 1c). Verify
that fault has been cleared and reassemble
phone with new transceiver board.
Check general condition of flex and flex
connector. If flex and connector are good,
check that display assembly mounting tabs
are fully engaged. If connector is not at fault,
proceed to b.
Replace transceiver board (refer to 1c). Verify
that fault has been cleared and reassemble
phone with new transceiver board.
Replace transceiver board (refer to 1c). Verify
that fault has been cleared and reassemble
unit with new transceiver board.
Replace microphone as described in
procedures. If fault is not cleared, proceed to
b.
Replace transceiver board (refer to 1c). Verify
that fault has been cleared and reassemble
phone with new transceiver board.
Check connection from earpiece to
transceiver board. If connection is not at fault,
proceed to b.
A920, A925
6881024B40-A