Motorola B89 Service Manual page 46

Troubleshooting
Table 3. PF A28 Telephone: Level 2 Troubleshooting Chart (Continued)
SYMPTOM
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.
42
PROBABLE CAUSE
d) Display board defective.
e) Transceiver board assembly
defective.
a) Faulty alert transducer.
b) Faulty transceiver board assembly. Replace the transceiver board assembly (refer
a) Microphone connections to the
transceiver board assembly defective.
b) Microphone defective.
c) Transceiver board assembly
defective.
a) Connections to or from transceiver
board assembly defective.
b) Connection to speaker faulty.
c) Earpiece speaker defective.
d) Antenna assembly defective.
May 15, 2001
Product Family B89
VERIFICATION AND REMEDY
Remove display board as described in the
procedures and replace with a known good
display board. Temporarily reassemble unit and
verify proper operation. If fault is cleared,
reassemble unit with the new display board. If
fault not cleared, proceed to e.
Replace the transceiver board assembly (refer
to 1c). Verify that the fault has been cleared and
reassemble the unit with the new transceiver
board assembly.
Replace alert transducer. Temporarily
reassemble the unit with the known good
transducer and verify the fault has been cleared.
If the transducer is not at fault, proceed to b.
to 1c). Verify that the fault has been cleared and
reassemble the unit with the new transceiver
board assembly.
Gain access to the microphone as described in
the procedures. Check connections. If connector
is faulty proceed to c; if the connector is not at
fault, proceed to b.
Gain access to microphone. Disconnect and
substitute a known good microphone. Place a
call and verify improvement in transmit signal as
heard by called party. If good, reassemble with
new microphone. If microphone is not at fault,
reinstall original microphone and proceed to c.
Replace the transceiver board assembly (refer
to 1c). Verify that the fault has been cleared and
reassemble the unit with the new transceiver
board assembly.
Gain access to the transceiver board assembly
as described in the procedures. Check flex and
the flex connector from the display board to the
transceiver board assembly. If flex is at fault,
replace front housing assembly. If flex connector
is at fault, proceed to d. If connection is not at
fault, proceed to b.
Remove the lens assembly as described in the
procedures. Inspect the mating contacts on the
speaker and on the display board. Repair
contacts or replace lens assembly and/or
display board as necessary. If speaker
connection not at fault, proceed to c.
Replace the lens assembly as described in the
procedures. Temporarily reassemble unit and
verify proper operation. If fault has not been
cleared, replace original lens assembly and
proceed to proceed to d.
Check to make sure the antenna is installed
correctly. If the antenna is installed correctly,
substitute a known good antenna assembly. If
this does not clear the fault, reinstall the original
antenna assembly and proceed to e.
6881038B20