Denon DRA-800H Service Manual page 80

3-3. Error Code H1-07 failure detection procedure
Checking device. (OSD)
Check the power supply voltage.
Check item(3-3.1.). Check the power supply volt-
age. :
Does the power supply voltage of the OSD [IC731]
indicate the appropriate voltage (1.8V, 3.3V)?
The test points are as follows.
6pin
IC731
93pin
1.8V
3.3V
YES
HDMI OSD [IC731] is faulty.
Replace with a new device.
Recheck from check item (3.1.).
If it does not work, replace the PCB.
NO Check item(3-3.2.). Check the power supply volt-
age. :
Check the power supply components [IC742/
IC741/Q7410] on the substrate and peripheral
pattern.
If there is no problem, remove the OSD [IC731]
from the substrate and measure the voltage at
the test point of check item (3-3.1.).
Is the voltage correct (1.8V or 3.3V)?
YES NO
The power supply circuit is faulty.
Replace the PCB.
Checking the reset waveform.
Check item(3-3.3.). Checking the reset :
Check the CPU.
When the power is turned on, is the TP"A_RST" waveform correct (as
shown in the figure)?
IC731
A_RST
YES NO
Check the reset circuit between CPU [IC751] and HDMI OSD [IC731].
If there is no problem, the HDMI OSD [IC731] is faulty.
Replace with a new device.
Recheck from check item (3.1.).
If it does not work, replace the PCB.
80
Examples of confirmation waveform
Voltage scale：1.0V/div
Time scale：20ms/div
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