Kenwood NX-300 Service Manual page 34

NX-300
● Checking the output signal
from the ASIC
Points to be checked
SBC R432
Points to be checked
/DRST C109
● The LCD displays control
Points to be checked
/LCDRST R406
Points to be checked
/CS4 IC402 (7 pin)
Points to be checked
5A IC708 (5 pin)
It is unlikely that the BGA parts are broken.
● When an error display appears on the LCD.
The LCD displays "INIT ERROR1".
The LCD displays "INIT ERROR2".
The LCD displays "INIT ERROR3".
■ Descriptions of signal names
1) RST(RESET) : ASIC reset signal
2) /BINT : Battery fi nal voltage monitoring
3) /PSW : Power switch signal
4) /FRST : FLASH reset signal
5) SBC : Switch B control
6) /DRST : DSP reset signal
7) /LCDRST : LCD reset signal
8) /CS4 : LCD controller chip select signal
9) 5A : Analog peripheral control 5.0V power supply
34
TROUBLE SHOOTING
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
3.3V
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
3.3V
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
3.3V
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
3.3V→0V→3.3V
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
5.0V
When a normal
value is confirmed.
LOW → Reset
LOW → Final voltage
LOW → ON
LOW → Reset
HIGH → ON
LOW → Reset
LOW → Reset
LOW → Active
Remove R432. If the ASIC side is 0V,
the ASIC/FLASH/SRAM may be broken.
If the /DRST is 0V, the ASIC/FLASH/SRAM are broken.
Remove R406. If the ASIC side is 0V,
the ASIC/FLASH/SRAM may be broken.
If the /CS4 is 0V or 3.3V, the ASIC/FLASH/SRAM
may be broken.
If 5A is 0V, parts other than the BGA are broken.
An error occurs when the ASIC internal RAM reads
or writes. The ASIC may be broken.
An error occurs when the DSP internal RAM reads
or writes. The DSP may be broken.
An error occurs when the SRAM internal RAM
reads or writes. The SRAM may be broken.