Motorola P7689, Service Manual, Page: 43 / 59

of 59 GSM Field Service Support 43
P7689 / P7789
Repair Chart
Table 2. GSM P7689 Cellular Telephone: Troubleshooting and Repair Chart. (Assembly Replacement
Level).
SYMPTOM PROBABLE CAUSE VERIFICATION AND
REMEDY
Personal telephone will not turn on or
stay on a) Battery pack either
discharged or defective Measure battery. If the battery voltage is <4.00 V dc,
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.
b) Battery connectors open
or misaligned. Visually inspect the 4 battery connectors on both the
battery assembly and the portable telephone.
If necessary, replace the battery. If battery is not at
fault, proceed to c
c) Logic/RF Board
Assembly
Defective. 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 (see personality transfer). Verify that the
fault has been cleared. If the fault has not been
cleared then proceed to d.
d) Display circuit failure 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
2. Personal telephone exhibits poor
reception and/or erratic operation
(such as calls frequently dropping,
Weak and/or distorted audio, etc.).
a) Antenna is defective Check to make sure that the antenna pin is properly
connected into the Logic/ RF assembly. If OK,
substitute a known good antenna and test in a call. If
the fault is still
present, proceed to b.
b) Logic/RF Board
Assembly
Defective. Replace Logic/RF Assembly (refer to symptom 1c).
Verify that the fault has been cleared and
Re-assemble the unit with the new PCB.
3. Display is erratic, or provides
Partial or no display.
a) Mating connections to /
from LCD Module faulty. Dissasemble unit, check display module is correctly
seated on PCB display pads, if necessary refit or
realign. If OK proceed to b.
b) LCD module is
Defective. Substitute a known good LCD module onto the
suspect board and connect to DC Pwr supply.
Depress
PWR and ensure display is now correct, if
Ok rebuild unit with new LCD module if LCD
module is not at fault proceed to c.
c) Logic/RF Board
Assembly
Defective. Replace Logic / RF Assembly (refer to symptom 1c).
Verify that the fault has been cleared and
Re-assemble the unit with the new PCB.
SYMPTOM PROBABLE CAUSE VERIFICATION AND REMEDY
4. Incoming call alert transducer
audio distorted or volume is too
low.
a) Faulty alert Transducer Remove suspect alert transducer from rear housing
and replace with known good alert. If fault does not
clear proceed to b)
b) Main RF / Logic PCB
defective Replace Logic/RF Board Assembly (refer to
symptom 1c). Verify that the fault has been cleared