Troubleshooting Chart - Motorola B89 Service Manual

Level III Service Manual

Troubleshooting Chart

Table 3. PF A28 Telephone: Level 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.
6881038B20
PROBABLE CAUSE
a) Battery either discharged or
defective.
b) Battery connectors open or
misaligned.
c) Transceiver board assembly
defective.
d) Keypad PCB failure.
a) Antenna assembly defective.
b) Transceiver board assembly
defective.
a) Transceiver board connections
faulty.
b) Display board connections faulty.
c) LCD module defective.
May 15, 2001
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 connectors 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 connectors
are not at fault, proceed to c.
Remove the transceiver board assembly.
Substitute a known good assembly and
temporarily reassemble the unit. Depress the
PWR button; if unit turns on and stays on,
disconnect the dc power source and reassemble
the telephone with the new transceiver board
assembly. Verify that the fault has been cleared.
If the fault has not been cleared then proceed to
d.
Replace the keypad PCB. Temporarily connect a
+3.6 Vdc supply to the battery connectors.
Depress the PWR button. If unit turns on and
stays on, disconnect the dc power source and
reassemble with the new keypad PCB.
Check to make sure that the antenna pin is
properly connected to the transceiver board
assembly. If connected properly, substitute a
known good antenna. If the fault is still present,
proceed to b.
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.
Remove rear housing from unit, check general
condition of flexible printed cable (flex). If the flex
is good, check that the flex connector is fully
pressed down. If not, check connector to
transceiver board connections. If faulty
connector, replace the transceiver board
assembly. If connector is not at fault, proceed to
b.
Remove the lens assembly as described in the
procedures. Inspect the flex and the flex
connector at the display board. Ensure the flex
connector is fully seated. Replace or correct as
required. If fault not cleared, proceed to c.
Remove the LCD module as described in the
procedures. Temporarily reassemble unit with a
known good LCD module and verify proper
operation. If fault is cleared, reassemble unit
with the new LCD module. If fault not cleared,
proceed to d.
Troubleshooting
41