Kenwood KRK-14H Service Manual page 13

Checking the output signal
from the MPU.
Checking the control signal output from the MPU.
Points to be checked
/FRST D13 (Anode side)
Points to be checked
/CS2_2 CN31
The LCD displays control
Points to be checked
53DC C194
18D C195
33D C201
The LCD displays control
Points to be checked
LCDRST
L50(CN37 side)
Points to be checked
/CS4 CP5 (8 pin)
It is unlikely that the BGA parts are broken.
When an error display appears on the LCD
The LCD displays "INIT ERROR 1".
Descriptions of signal names
1) /PRST :MPU reset signal
2) /FRST :Flash Memory reset signal
3) /CS2_2 :Flash Memory chip select signal
4) LCDRST :LCD reset signal
5) /CS_4 :LCD controller chip select signal
When a normal
value is confirmed.
When an abnormal
value is confirmed.
Normal voltage
1.8V
When a normal
value is confirmed.
Normal voltage
When an abnormal
After power-on,
value is confirmed.
and
1.8V 0V 1.8V,
1.8V fixed later
When a normal
value is confirmed.
When an abnormal
Normal voltage
value is confirmed.
5.3V
1.8V
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
Normal voltage
value is confirmed.
After power-on, and
When a normal
value is confirmed.
LOW
LOW
LOW
LOW
LOW
If the /FRST is always 0V ,the MPU is broken.
Remove D13 to check the voltage of Flash
Memory side R167.
If the voltage becomes abnormal, Flash Memory
is broken.
Remove R164.
If the voltage of MPU side becomes 0V or 1.8V,
MPU is broken.
If the voltage of MPU side becomes normal,
Flash Memory or chip resistor(R164) may be broken.
The BGA parts are not broken.
Remove the FFC to Sub (Display) unit of the
NX-5700/5800 and KCH-19.
If the voltage becomes normal, the FFC or
Sub (Display) unit is broken.
Remove Q10.
If the MPU side is 3.3V,
the MPU or Flash memory or mobile DDR
may be broken.
/CS4 has an abnormal voltage.
Check each of the following items.
Check to see the terminal of L43 and CP5.
Remove the FFC to Sub (Display) unit of the
NX-5700/5800 and KCH-19.
As a result, if the abnormality yet,
the MPU or Flash Memory or mobile DDR may
be broken.
An error occurs when the mobile DDR internal
RAM reads or writes.
The mobile DDR may be broken.
Check the flowchart from beginning.
Reset
Reset
Active
(L50 CN37 side) Reset
Active
(No.RA021<Rev.001>)1-13