Marantz SR5012 Service Manual page 117

When the results of check item (50) are "00"
(Detection of 5V is not OK.)
Check the +5V voltage. (Front HDMI Buffer)
Check item(52). Check the +5V voltage :
Does "+5 V" at the following test point indicate 5 V?
The test points are as follows.
70 pin
U1000
5V
YES
HDMI Rx1 [U1000] is faulty.
Replace with a new device.
Recheck from check item (2).
If it does not work, replace the PCB.
NO
Check for a short circuit in the 5 V line, the
Front HDMI FFC, and the 5 V Switch [U1002].
If there is no problem, the HDMI Rx1 [U1000]
or the 5 V Switch [U1002] is faulty.
Replace with a new device.
When the results of check item (51) are "00 or
(If the DDC are not OK)
Check the DDC line. (Front HDMI Buffer)
Check item(53). Check the DDC line :
Does "DDCCL / DDCDA" signal of the Rx1 [U1000]
indicate 5 V?
The test points are as follows.
74/75 pin
U1000
YES
HDMI Rx1 [U1000] is faulty.
Replace with a new device.
Recheck from check item (2).
If it does not work, replace the PCB.
117
04"
less than 100KHz
5V
5V
This diagram shows an example of the DDC communica-
tion 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 and
check the Front HDMI FFC.
If there is no problem, the Front HDMI Buffer
[U3000] is faulty.
Replace with a new device.