Denon DRA-800H Service Manual page 88

When the results of check item (3-7.1.) are "00"
(Detection of 5V is not OK)
Check the +5V voltage. (HDMI Rx/Tx)
Check item(3-7.3.). Check the +5V voltage.
Does "+5V" at the following test point indicate 5 V? [JK731/JK741]
JK741 JK731
HDMI 5 HDMI 4
[MEDIA PLAYER] [GAME]
+5V +5V
YES
HDMI Rx/Tx [IC721] is faulty.
Replace with a new device.
Recheck from check item (3.2.).
If it does not work, replace the PCB.
NO
Check for a short circuit in the 5 V line and the 5
V Switch IC [IC733].
If there is no problem, the HDMI Rx/Tx [IC721] or
the 5 V Switch IC [IC733] is faulty
Replace with a new device.
When the results of check item (3-7.2.) are
(Detection of DDC is not OK.)
Check the DDC line. (HDMI Rx/Tx)
Check item(3-7.4.). Check the DDC line :
Are waveforms of "DDCSCK" and "DDCSDA" observed at the test point near the HDMI input terminal?
JK741 JK731
HDMI 5 HDMI 4
[MEDIA PLAYER] [GAME]
DDCSCK
DDCSDA
YES
HDMI Rx/Tx [IC721] is faulty.
Replace with a new device.
Recheck from check item (3.2.).
If it does not work, replace the PCB.
88
"00 or 04"
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.
Voltage scale：2.0V/div
Time scale：40us/div
NO
Check for a short circuit in the DDC line.
If there is no problem, the HDMI Rx/Tx [IC721] is
faulty.
Replace with a new device.