Troubleshooting - Kenwood NX-5800 Service Manual

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/DSP (IC706), mobile DDR (IC702), Flash memory (IC701)
When the BGA IC is problematic, please bring the printed circuit board (XC1-0391-82/XC1-0391-83) in for service. Various ESN/
default adjustment values are written on the printed circuit board for service.
Additionally various ESN stickers are included. (Please refer to "5.4 Replacing Main Unit".)
After the printed circuit board has been readjusted, please attach any ESN stickers to the chassis. When "ESN Validation" is used,
you must modify the ESN register.
Checking power supply voltage
Checking voltage
Points to be checked
12M C39
18M C64
33M IC5 (5 pin)
18M_3 IC9 (1 pin)
Power supply of each device is connected through
the coil.
[MPU/DSP]
12M L714, L715, L717
18M L720, L721
33M L722
[mobile DDR]
18M L702
[Flash Memory]
33M L700
18M_3 L724
Checking the clock
Checking the clock
Points to be checked
19.2MHz
MPU/DSP side R708
Checking the Reset/Control signal
Checking the control signal input to the MPU/DSP
Points to be checked
/RST D12 (Anode side)
/BINT IC2 (13 pin)
/OVRB_OUT IC2 (12 pin)
Checking the MPU/DSP input switch signal
The POWER key is pressed and held.
Points to be checked
/PSW_OUT IC2 (15 pin)
The ignition key is kept ON.
Points to be checked
/IGN_OUT IC2 (9 pin)
1-106 (No.RA017<Rev.003>)
SECTION 5

TROUBLESHOOTING

Normal voltage
1.2V
1.8V
3.3V
1.8V
When an abnormal
value is confirmed.
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage (1.2V)
19.2MHz
When a normal
value is confirmed.
Normal voltage
1.8V
When an abnormal
3.1V
value is confirmed.
3.1V
When a normal
value is confirmed.
Confirmed voltage
ON 0V
Confirmed voltage
ON 0V
When an abnormal
value is confirmed.
When a normal
value is confirmed.
Checking for an abnormal point
12M has an abnormal voltage.
[MPU/DSP]
Remove L714 and L715 and L717 to check
the voltage of the 12M.
If the voltage becomes normal, the MPU/DSP
is broken.
Note:
A1(12M DC/DC Converter Device) is fragile
in the scratch.
Be careful when you touch this parts.
18M has an abnormal voltage.
[MPU/DSP]
Remove L720 and L721 to check the voltage
of the 18M.
If the voltage becomes normal, the MPU/DSP
is broken.
[mobile DDR]
Remove L702 to check the voltage of the 18M.
If the voltage becomes normal, the mobile DDR
is broken.
33M has an abnormal voltage.
[MPU/DSP]
Remove L722 to check the voltage of the 33M.
If the voltage becomes normal, the MPU/DSP
is broken.
[Flash Memory]
Remove L700 to check the voltage of the 33M.
If the voltage becomes normal, Flash memory
is broken.
18M_3 has an abnormal voltage.
[Flash Memory]
Remove L724 to check the voltage of the
18M_3. If the voltage becomes normal,
Flash memory is broken.
If the voltage is not corrected, there is a
problem other than the BGA parts. *1
The BGA parts are not broken.
The BGA parts are not broken.
Check the peripheral circuit of IC2. *2