DBTEL DB-6568, Руководство по обслуживанию

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DBTEL Incorporated
DB-6568 Service Manual Level 1 ~ 3
2003.11.13
DBTEL Copyright Reserved
Page 30 of 66
The frequently seen handset defects are normally not more than 10 types, such as fail
to power on, drop into water, broken that caused by dropping, no display, … etc.
However, the cause of malfunction is so diversity that needs to record the malfunction
for clarifying and action taken. In addition to symptom clarifying, both technician and
user will reach the agreement on repairing based on the record. Technician is strongly
advised to check for any other defect in some other components or parts.
三、
Recording the model number and IMEI code
Every handset has it's own unique IMEI code for easy identification.
四、
Familiar with operation command
It is essential that service/repair technician must be familiar with operation command of
the handset like menu setting and its function.
五、
Repairing handset in workshop
Do not fix handset in front of user if do not certain of the defect. Otherwise, another
defect might occur if servicing in nervous. Disassemble the handset only for checking is
allowed.
六、
From simple to complex; and easy to difficulty
This is a basic principle of maintenance. Do not disassemble the handset unless it can
hardly be determined by checking the surface or operation of handset.
七、
Checking PCBA carefully
Some of the defects can be detected visibly and no further testing procedures is
required. For example, IC wouldn't generate high temperature while working; if high
temperature is perceived instead, there might be short-circuited to IC internal circuit or
loading. In genera, we can find some clue of malfunction by direct inspections. But
，
direct inspection was based on experiences.
八、
Power On
After performing the procedures as described above, adjust the output voltage of DC
power supply to appropriate rating, connect serially to a voltage meter, power on the
handset and check that the output voltage is nominal rating. If not, it is defected.
Compare the detected voltage with the normal idle voltage to determine the scope of
defect.
九、
Checking power supply circuit
Check the battery voltage, internal input voltage and DC power supply to verify that the
rating is normal. Most of the defects are possibly caused by power supply.
十、
Checking software performance
十一、
Check that the audio tone input/output port, SIM card, ringer, keypad, LCD