Check item(24).
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?
U1018
AVSDA AVSCL
Check item(25).
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.
Check the I2C communication line.
GUI [
U1026
] is faulty.
Replace with a new device.
GUI [
U1026
] is faulty.
Replace with a new device.
YES
*The diagram shows an example.
(Signal patterns vary depending on the
timing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- SCL frequency (400 kHz normally)
Voltage scale:1.0V/div
Time scale:10us/div
NO
YES
YES
NO
Recheck from
check item (1).
If it does not work, replace the PCB.
Before Servicing
This Unit
Electrical
Mechanical
Repair Information
Updating
102