Repair Chart - Motorola T189 Service Manual

6.4 Repair Chart

Table 2. GSM T189 Cellular Telephone: Troubleshooting and Repair Chart. (Assembly Replacement
Level).
SYMPTOM
Personal telephone will not turn on or
stay on
2. Personal telephone exhibits poor
reception and/or erratic operation (such
as calls frequently dropping, weak
and/or distorted audio, etc.).
3. Display is erratic, or provides
Partial or no display.
PROBABLE CAUSE
a) Battery pack either
discharged
or defective
b) Battery connectors open
or
misaligned.
c) Logic/RF Board
Assembly
Defective.
d) Display circuit failure
a) Antenna is defective
b) Logic/RF Board Assembly
Defective.
a) Mating connections to /
from
Display PCB.
b) Display Module is
Defective.
VERIFICATION AND
REMEDY
Replace batteries with known good cells.
Power unit
on. If unit powers on OK replace batteries.
If battery is not at fault, proceed to b.
Visually inspect the battery connectors on
the rear
housing top and bottom. Check for bad
alignment or
dirty contacts. Re-align, clean and, if
necessary,
replace the rear housing. If battery
connectors are not
at fault, proceed to c
Remove the Logic/RF 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 Logic/RF
Board
assembly. If unit does not power up
proceed to d)
Disassemble unit and remove LCD
module and
insert known good module. Insert Battery
and
depress PWR button. Ensure unit stays
on, if OK
reassemble unit in new housing assembly
Check to make sure that the antenna is
properly
inserted into the front housing. If OK,
substitute a
known good antenna. If the fault is still
present,
proceed to b.
Replace Logic/RF Assembly (refer to
symptom 1c).
Verify that the fault has been cleared and
Re-assemble the unit with the new PCB.
Dissasemble unit, and remove display
module from
main PCB, check connector for any signs
of
corrosion or damage. If damaged proceed
to c)
Substitute a known good Display Module
onto the
suspect main board and connect to DC
Pwr supply
depress PWR and ensure display is now