YES
YES
YES
YES
Checking the reset waveform (HDMI Rx/Tx)
Check the I2C communication line. (HDMI Rx/TX)
Check item(8).
Checking the reset waveform :
Check the waveform.
Is the "I2C" waveform of the TP near the HDMI Rx (
IC721
115pin
)
correct (like the one shown in the diagram) when the power is
turned on?
115pin
Check item(9).
Check the I2C communication line :
Check the CPU.
Is the "I2C" waveform of the TP near the HDMI Rx (
U1000
)
correct (like the one shown in the diagram) when the power is
turned on?
116pin
PSDA
114pin
PSCL
Check the reset circuit between
CPU (
IC751
) and HDMI Rx/Tx
(
IC721
).
If there is no problem, the HDMI
Rx (
IC721
) is faulty.
Replace with a new device.
Recheck from
check item (2)
.
If it does not work, replace the
PCB.
The HDMI Rx/Tx
(
IC721
) is faulty.
Replace with a new
device.
HDMI SW (
IC701
)
is faulty. Replace with
a new device.
CPU(
IC751
)
is faulty. Replace with
a new device.
The HDMI Rx/Tx (
IC721
) is faulty.
Replace with a new IC.
Recheck from
check item (2).
If it does not work, replace the PCB.
Check item(10).
Check the I2C com-
munication line :
Check HDMI Rx/Tx (
IC721
), and
CPU(
IC751
) patterns as well as solder-
ing.
If there is no problem, go to the next
step.
Checking the HDMI SW.
Remove the damping resistor
R7136
/
R7138
of
IC701
.
Is the "I2C" waveform correct?
Recheck from
check item (2).
If it does not work, replace the PCB.
Checking the HDMI Rx/Tx.
Remove the damping resistor
R7229
/
R7231
of
IC721
.
Is the "I2C" waveform correct?
NO
NO
NO
YES
YES
NO
Examples of confirmation waveform
*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 )
77
Caution in
servicing
Electrical
Mechanical
Repair Information
Updating
