Kenwood NX-800 Service Manual page 43

When a normal value
is comfirmed.
● Checking the signal output
from the ASIC by software
control
Points to be checked
SBC R408
When a normal value
is comfirmed.
Points to be checked
/DRST R841
When a normal value
is comfirmed.
● Panel control (TX-RX unit)
Points to be checked
/PRST R506 (Signal side)
When a normal value
is comfirmed.
Points to be checked
80C C581 (Signal side)
When a normal value
is comfirmed.
● Panel control (TX-RX unit)
Checking voltage
Points to be checked
5C IC903 (5 pin)
33C IC904 (5 pin)
When a normal value
is comfirmed.
Checking the clock/reset
Points to be checked
Xout R948
/PRST R947 (Signal side)
FLASH R986
When a normal value
is comfirmed.
Checking the Control signal
Points to be checked
/CS0 IC911 (48 pin)
/RD IC911 (42 pin)
When a normal value
is comfirmed.
Checking the Control signal
Points to be checked
/LCDRST R991 (Signal side)
/CS3 IC912 (7 pin)
When a normal value
is comfirmed.
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".
TROUBLE SHOOTING
When an abnormal
value is comfirmed.
Normal voltage
3.3V
When an abnormal
value is comfirmed.
Normal voltage
3.3V
When an abnormal
value is comfirmed.
Normal voltage
3.3V
When an abnormal
value is comfirmed.
Normal voltage
8.0V
When an abnormal
value is comfirmed.
Normal voltage
5.0V
3.3V
When an
Normal voltage
abnormal
11.059MHz (5.0V)
value is
5.0V
comfirmed.
3.3V
Normal voltage
3.3V→0V→3.3V
When an abnormal
3.3V→0V→3.3V
value is comfirmed.
When an abnormal
value is comfirmed.
Normal voltage
3.3V
3.3V→0V→3.3V
Remove R408. If the ASIC side is 0V,
the ASIC/FALSH/SRAM may be broken.
If the /DRST is 0V, the ASIC/FALSH/SRAM are broken.
Remove the Q501. If the ASIC side is 0V,
the ASIC/FALSH/SRAM may be broken.
If the SBC is 3.3V and 80C regulator $IC403 (pin 1)
input side is 8.5V or more, the BGA parts are not broken.
The BGA parts are not broken.
If nothing is displayed even after replacing the panel,
the BGA may be broken.
The panel microcomputer receives a request of LCD
display from the ASIC. Then, the LCD displays.
The /LCDRST and /CS3 signal become abnormal if
communication is disabled due to a trouble in
the ASIC.
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.
NX-800
43