Denon AVR-S750H - Page 95

Check item(3-6.1.). Check the power supply volt-
age. :
Does the power supply voltage of the DIR [IC761]
indicate the appropriate voltage (3.3V)?
The test points are as follows.
IC761
C7602
Check item(3-6.2.). Check the power supply volt-
age. :
Check the power supply components [IC741/
Q7415] on the substrate and peripheral pattern.
If there is no problem, remove the DIR [IC761]
from the substrate and measure the voltage at
the test point of check item (3-6.1.).
Is the power supply voltage correct (3.3V)?
Check the power supply voltage.
Checking device. [IC761 : PCM9211]
Go to next page.
3-6. Error Code H1-12 failure detection procedure
NO
DIR [IC761] is faulty.
Replace with a new device.
Recheck from check item (3.1.).
If it does not work, replace the PCB.
The power supply circuit is faulty.
Replace the PCB.
NOYES
YES
Check item(3-6.3.). Checking the reset :
Check the CPU.
When the power is turned on, is the DIR [IC761 : 34pin] waveform
correct (as shown in the gure)?
IC761
34pin
3.3V
Checking the reset waveform.
Recheck from check item (3.1.).
If it does not work, replace the PCB.
Check the reset circuit between CPU [IC751] and DIR [IC761].
If there is no problem, the DIR [IC761] is faulty.
Replace with a new device.
NOYES
Examples of conrmation waveform
Voltage scale：1.0V/div
Time scale：20ms/div
Before Servicing
This Unit
Electrical Mechanical Repair Information Updating
95