When the results of check item (13) are "
NO
"
(Detection of 5V is not OK)
When the results of check item (14) are "
00 or 04
"
(Detection of DDC is not OK.)
Check item(15).
Check the +5V voltage.
Does the test point near HDMI input terminal (
JK391/JK392/JK393
) indicate 5V?
JK391
JK392
JK393
5V
5V
5V
Check item(16).
Check the DDC line :
Are waveforms of "
DDCSCK
" and "
DDCSDA
" observed at the test point near the HDMI input
terminal(
JK391/JK392/JK393
)?
JK391
JK392
JK393
DDCSCK
DDCSDA
Check the +5V voltage. (HDMI IN5 - 7)
Check the DDC line. (HDMI IN5 - 7)
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.
Check for a short circuit in the 5 V line and the 5
V Switch IC (
IC392
).
If there is no problem, the HDMI Switcher1 (
IC391
)
or the 5 V Switch IC (
IC392
) is faulty
Replace with a new device.
Check for a short circuit in the DDC line.
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.
YES
NO
YES
NO
less than 100KHz
5V
5V
This diagram shows an example of the DDC commu-
nication waveform.
-The high level voltage is 5V.
-The frequency of the DDC CLK is 100 KHz or less.
Check at each test point.
100
Caution in
servicing
Electrical
Mechanical
Repair Information
Updating
