Trouble Shooting - Kenwood NX-411 Service Manual

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 (IC309), DSP (IC304), FLASH (IC303), SRAM (IC305)
When the BGA IC is problematic, please bring the printed circuit board (X57-8120-11) in for service. Various ESN/default ad-
justment values are written on the printed circuit board for service.
Additionally various ESN stickers are included. (Please refer to pages 35 and 36.)
Button type lithium battery (W09-0971-05) does not belong to the printed circuit board for service. Please use the part which
has been attached to the printed circuit board. After the printed circuit board has been readjusted, please attach any ESN
stickers to the chassis. When "ESN Validation" is used with NXDN Trunking, you must modify the ESN register.
● Checking power supply voltage
Checking voltage
Points to be checked
33M IC203 (3 pin)
15M IC202 (4 pin)
33A IC201 (3 pin)
31BU IC210 (3 pin)
Power supply of each device is connected through the coil.
[ASIC]
33M: L318, 15M: L317, 33A: L315
[DSP]
33M: L313, 15M: L310
[FLASH]
33M: L306
[SRAM]
31BU: L308
● Checking the clock
Checking the clock
Points to be checked
18.432MHz ASIC side R372
ASIC & DSP side R373
32.768kHz IC308 (1 pin)
● Checking the Reset/Control signal
Checking the control signal input to the ASIC
Points to be checked
RESET IC306 (4 pin)
/BINT Q204 (6 pin)
/PSW Q203 (3 pin)
Checking the control signal output from the ASIC
Points to be checked
/FRST IC303 side C332

TROUBLE SHOOTING

When an abnormal
value is confirmed.
Normal voltage
3.3V
1.5V
3.3V
3.1V
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage (3.3V)
18.432MHz
18.432MHz
32.768kHz
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
3.3V
3.3V
3.3V
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
3.3V
When a normal
value is confirmed.
Checking for an abnormal point
33M has an abnormal voltage.
[ASIC]
Remove L318 to check the voltage of the 33M.
If the voltage becomes normal, the ASIC is broken.
[DSP]
Remove L313 to check the voltage of the 33M.
If the voltage becomes normal, the DSP is broken.
[FLASH]
Remove L306 to check the voltage of the 33M.
If the voltage becomes normal, the FLASH is broken.
15M has an abnormal voltage.
[ASIC]
Remove L317 to check the voltage of the 15M.
If the voltage becomes normal, the ASIC is broken.
[DSP]
Remove L310 to check the voltage of the 15M.
If the voltage becomes normal, the DSP is broken.
33A has an abnormal voltage.
[ASIC]
Remove L315 to check the voltage of the 33A.
If the voltage becomes normal, the ASIC is broken.
31BU has an abnormal voltage.
[SRAM]
Remove L308 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.
Parts other than the ASIC/FLASH/SRAM are broken.
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.
NX-411
33