Kenwood NX-3720, Service Manual

Page: 153 / 210

(No.RA054<Rev.001>)1-153
Checking the output signal
from the MPU/DSP.
Fail
Fail
Fail
Pass
Points to be checked Normal voltage
SBC MPU/DSP side R62 3.2V
Remove R62 to check the voltage of the SBC.
If the MPU/DSP side is 0V,
the MPU/DSP or Flash memory or mobile DDR
may be broken.
Fail
Fail
Fail
Pass
Pass
Pass
Pass
The LCD displays control
The LCD displays control
It is unlikely that the BGA parts are broken.
Points to be checked Normal voltage
PRST
D410(Cathode side) 3.2V
Points to be checked
Normal voltage
/FRST
D401(Anode side)
Points to be checked Normal voltage
/CS_LCD CP412(8pin)
After power-on,
and
1.8V fixed later
1.8V 0V 1.8V,
After power-on,
and
/CS_LCD has an abnormal voltage.
Check each of the following items.
Check to see the terminal of L419 and CP412.
Remove the FFC of TX-RX unit between
Sub (Display) Unit.
As a result, if the abnormality yet, the MPU/DSP or
Flash memory or mobile DDR may be broken.
Remove Q403.
If the MPU/DSP side is 3.2V, the MPU/DSP or Flash
memory or mobile DDR may be broken.
Points to be checked Normal voltage
54M C520
18M C519
32M C511 5.36V
1.8V
3.2V
The BGA parts are not broken.
Remove the FFC of TX-RX unit between Sub
(Display) unit.
If the voltage becomes normal, the FFC or Sub
(Display) unit is broken.
The LCD display “INIT ERROR 1”.
An error occurs when the mobile DDR internal
RAM reads or writes.
The mobile DDR may be broken.
Check the flowchart from beginning.
1) /RST : MPU/DSP reset signal LOW Reset
2) /BINT : Battery final voltage monitoring LOW Final voltage
3) /OVRB_OUT : Battery overvoltage monitoring LOW Overvoltage
4) /PSW_OUT : Power switch signal LOW ON
5) /IGN_OUT : Ignition switch signal LOW ON
6) /FRST : Flash Memory reset signal HIGH Reset
7) /CS_F : Flash Memory chip select signal LOW Active
10) /CS_LCD : LCD controller chip select signal LOW Active
9) PRST : LCD reset signal HIGH Reset
8) SBC : B control HIGH ON
1.8V
1.8V fixed later
Checking the control signal output from the MPU/DSP
Remove D401 to check the voltage of Flash memory
side R433.
If the voltage becomes abnormal, Flash memory is
broken.
If the /FRST is always 0V, the MPU/DSP is broken.
Pass
Points to be checked Normal voltage
/CS_F IC403(4pin)
If the IC403 (1pin) is 0V or 1.8V,
the MPU/DSP may be broken.
If the IC403 (2pin) is 0V or 1.8V,
the MPU/DSP or Flash memory may be broken.
1.8V 0V 1.8V,
Pass
When an error display appears on the LCD
Descriptions of signal names