YES
YES
YES
YES
Checking the reset waveform. (HDMI Switcher1)
Check the I2C communication line. (HDMI Switcher1)
Check item(10).
Checking the reset waveform :
Check the waveform.
Is the "
S1_RST
" waveform of the TP near the HDMI Switcher1
(
IC391
) correct (like the one shown in the diagram) when the
power is turned on?
IC391
S1_RST
Check item(11).
Check the I2C communication line :
Check the CPU.
Is the "
P_DA, P_CK
" waveform of the TP near the HDMI Switch-
er1 (
IC391
) correct (like the one shown in the diagram) when
the power is turned on?
IC391
P_CK
P_DA
Check the reset circuit between
CPU (
IC151
) and HDMI Switcher1
(
IC391
).
If there is no problem, the HDMI
Switcher1 (
IC391
) is faulty.
Replace with a new device.
Recheck from
check item (3)
.
If it does not work, replace the
PCB.
HDMI Switcher1
(
IC391
) is faulty.
Replace with a new
device.
HDMI Switcher2
(
IC381
) is faulty.
Replace with a new
device.
HDMI Tx (
IC431
) is
faulty.
Replace with a new
device.
CPU (
IC151
) is faulty.
Replace with a new
device.
HDMI Switcher1 (
IC391
) is faulty.
Replace with a new device.
Recheck from
check item (3).
If it does not work, replace the PCB.
Check item(12).
Check the I2C com-
munication line :
Check HDMI Switcher1, 2 (
IC391 or
IC381
), HDMI Tx (
IC431
) and CPU
(
IC151
) patterns as well as soldering.
If there is no problem, go to the next
step.
Check the HDMI Switcher2
Remove the damping resistor
(
R3812/R3814
) of (
IC381
).
Is the "
I2C
" waveform correct?
Recheck from
check item (3).
If it does not work, replace the PCB.
Check the HDMI Tx.
Remove the damping resistor
(
R4326/R4328
) of (
IC431
).
Is the "
I2C
" waveform correct?
Check the HDMI Switcher1
Remove the damping resistor
(
R3914/R3916
) of (
IC391
).
Is the "
I2C
" waveform correct?
NO
NO
NO
NO
YES
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 )
104
Caution in
servicing
Electrical
Mechanical
Repair Information
Updating
