TK-5210
(
G
)
43
TROUBLE SHOOTING
Fault diagnosis of the BGA (Ball Grid Array) IC
■
Overview
A
fl owchart 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
ASIC (IC10), DSP (IC3), FLASH (IC1), SRAM (IC4)
When the BGA IC is problematic, please bring the printed circuit board (X53-4390-13 for basic, X53-4390-14 for 4-key, X53-
4390-15 for DTMF keypad) in for service.
●
Checking power supply voltage
Checking voltage
Points to be checked
Normal voltage
33M IC705 (5 pin)
3.3V
15M IC709 (4 pin)
1.5V
33A IC710 (5 pin)
3.3V
31BU IC17 (3 pin)
3.1V
Power supply of each device is connected through the coil.
[ASIC]
33M: L16, 15M: L17, 33A: L19
[DSP]
33M: L9, 15M: L5
[FLASH]
33A: L4
[SRAM]
31BU: L6
●
Checking the clock
Checking the clock
Points to be checked
Normal voltage (3.3V)
18.432MHz ASIC side R80 18.432MHz
DSP side R81 18.432MHz
32.768kHz IC7 (1 pin)
32.768kHz
When a normal
value is confirmed.
When a normal
value is confirmed.
●
Checking the Reset/Control signal
Checking the control signal input to the ASIC
Points to be checked
Normal voltage
RESET IC5 (4 pin)
3.3V
/BINT Q7 (6 pin)
3.3V
PSW Q8 (3 pin)
3.3V
Checking the control signal output from the ASIC
Points to be checked
Normal voltage
/FRST C22
3.3V
If the /FRST is always 0V, the ASIC is broken.
If the /FRST repeats 3.3V and 0V at intervals,
the ASIC, FLASH and SRAM may be broken.
The BGA parts are not broken.
The BGA parts are not broken.
Checking for an abnormal point
33M has an abnormal voltage.
[ASIC]
Remove L16 to check the voltage of the 33M.
If the voltage becomes normal, the ASIC is broken.
[DSP]
Remove L9 to check the voltage of the 33M.
If the voltage becomes normal, the DSP is broken.
15M has an abnormal voltage.
[ASIC]
Remove L17 to check the voltage of the 15M.
If the voltage becomes normal, the ASIC is broken.
[DSP]
Remove L5 to check the voltage of the 15M.
If the voltage becomes normal, the DSP is broken.
33A has an abnormal voltage.
[ASIC]
Remove L19 to check the voltage of the 33A.
If the voltage becomes normal, the ASIC is broken.
[FLASH]
Remove L4 to check the voltage of the 33A.
If the voltage becomes normal, the FLASH is broken.
31BU has an abnormal voltage.
[SRAM]
Remove L6 to check the voltage of the 31BU.
If the voltage becomes normal, the SRAM is broken.
If the voltage is not corrected, there is a problem
other than the BGA parts.
When an abnormal
value is confirmed.
When an abnormal
value is confirmed.
When an abnormal
value is confirmed.
When an abnormal
value is confirmed.
When a normal
value is confirmed.
●
Checking the output signal
from the ASIC
Points to be checked
Normal voltage
SBC TP7
3.3V
When an abnormal
value is confirmed.
When a normal
value is confirmed.
When a normal
value is confirmed.
Points to be checked
Normal voltage
/DRST C21
3.3V
If the /DRST is 0V, the ASIC/FLASH/SRAM are broken.
Remove R166, R161 and R270. If the ASIC side is 0V,
the ASIC/FLASH/SRAM may be broken.
When a normal
value is confirmed.
When an abnormal
value is confirmed.
