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5.1
Fault Diagnosis of the BGA (Ball Grid Array) IC
Overview
A flowchart for determining whether or not the transceiver can be powered on (the LCD does not function even if the power
switch is turned on) due to broken BGA parts.
BGA parts
MPU (IC14), mobile DDR (IC24), Flash memory (IC30)
Checking SB (Battery) voltage
Points to be checked
SB
CN2
NOTE:
Because it depends on the battery performance, it may be
less than the voltage value that has been described above.
Checking power supply voltage
Checking voltage
Points to be checked
12D R68
18D R74
33D R66
18D_Flash R101
Power supply of each device is connected through the coil.
[MPU]
12D: L9, L10, L11, L12, L13
18D: L14, L15
33D: L20
[mobile DDR]
18D: L33
[Flash Memory]
33D: L35
18D_Flash: L34
Checking the clock
Checking the clock
Points to be checked
19.2MHz
MPU side R70
Checking the Reset/Control signal
Checking the control signal input to the MPU
Points to be checked
/RST D34 (Anode side)
1-14 (No.RA027<Rev.001>)
SECTION 5
TROUBLESHOOTING
When an abnormal
Normal voltage
value is confirmed.
13.6V 15%
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
1.2V
1.8V
3.3V
1.8V
When a normal
value is confirmed.
Normal voltage (1.2V)
When an abnormal
19.2MHz
value is confirmed.
When a normal
value is confirmed.
Normal voltage
When an abnormal
1.8V
value is confirmed.
When a normal
value is confirmed.
The BGA parts are not broken.
If the CN2 is 0V or unstable, check the SB
output of NX-5700/5800 Main unit.
Checking for an abnormal point
12D has an abnormal voltage.
[MPU]
Remove L9~L13 to check the voltage of the 12D.
If the voltage becomes normal, the MPU is broken.
NOTE:
A1(12D DC/DC Converter Device) is fragile
in the scratch.
Be careful when you touch this parts.
18D has an abnormal voltage.
[MPU]
Remove L14 and L15 to check the voltage
of the 18D.
If the voltage becomes normal, the MPU is broken.
[mobile DDR]
Remove L33 to check the voltage of the 18D.
If the voltage becomes normal, the mobile
DDR is broken.
33D has an abnormal voltage.
[MPU]
Remove L20 to check the voltage of the 33D.
If the voltage becomes normal, the MPU is broken.
[Flash memory]
Remove L35 to check the voltage of the 33D.
If the voltage becomes normal, Flash memory
is broken.
18D_Flash has an abnormal voltage.
[Flash memory]
Remove L34 to check the voltage of the 18D_Flash.
If the voltage becomes normal, Flash memory
is broken.
If the voltage is not corrected, there is a problem
other than the BGA parts.
The BGA parts are not broken.
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