Check item(55).
Checking the reset :
Check the CPU.
Is the waveform of the TP near the GUI(
U1026
) correct (like the one
shown in the diagram) when the power is turned on?
Check item(56).
Check the I2C communication line :
Check the CPU.
Is the "I2C" waveform of the TP near the CPU(
U1018
) correct (like
the one shown in the diagram) when the power is turned on?
Check item(57).
Check the I2C communication line :
Check GUI (
U1026
), HDMI SW(
U1103
) and CPU(
U1018
) patterns as well as soldering.
If there is no problem, go to the next step.
Check the CPU.
Remove the damping resistor (
R1493/R1494
)
of (
U1018
).
Is the "I2C" waveform correct?
The CPU(
U1018
) is faulty. 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 (
U1026
) is faulty.
Replace with a new device.
The GUI (
U1026
) 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 (
U1018
) and GUI (
U1026
).
If there is no problem, the GUI (
U1026
) 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
103
Caution in
servicing
Electrical
Mechanical
Repair Information
Updating
