Check item(74).
Checking the reset :
Check the CPU.
Is the waveform of the TP"
TP113
"near the GUI(
IC401
) correct (like
the one shown in the diagram) when the power is turned on?
IC401
TP113
Check item(75).
Check the I2C communication line :
Check the CPU.
Is the waveform of the TP"
TP110/111
"near the GUI(
IC401
) correct
(like the one shown in the diagram) when the power is turned on?
IC401
TP111
TP110
Check item(76).
Check the I2C communication line :
Check GUI (
IC401
), HDMI Decoder (
IC351
) and CPU(
IC151
) patterns as well as soldering.
If there is no problem, go to the next step.
Check the HDMI Decoder.
Remove the damping resistor (
R3532/R353
)
of HDMI Decoder (
IC351
).
Is the "
I2C
" waveform correct?
The GUI (
IC401
) is failure.
Replace with a new device.
Checking the reset waveform.
Check the I2C communication line.
10ms
10ms
10ms
Example of the waveform to be checked
The GUI (
IC401
) is failure.
Replace with a new device.
HDMI Decoder (
IC351
) is faulty.
Replace with a new device.
YES
Recheck from
check item (1).
If it does not work, replace the PCB.
Check the reset circuit between CPU (
IC151
) and GUI (
IC401
).
If there is no problem, the GUI (
IC401
) is faulty.
Replace with a new device.
NO
YES
*The diagram shows an example.
(Signal patterns vary depending on
the timing.)
Points for checking waveforms
- Crest value (3.3 V normally)
- Signal change
- SCL frequency (400 kHz normally )
NO
YES
YES
NO
Recheck from
check item (1).
If it does not work, replace the PCB.
123
Caution in
servicing
Electrical
Mechanical
Repair Information
Updating
