Denon AVR-X6400H Service Manual page 106

Check the I2C communication line.
YES
Check item(20). Check the I2C communication line :
Check the CPU.
Is the "I2C" waveform of the TP near the [U2000] correct (like the
one shown in the diagram) when the power is turned on?
R2033 I2C(AVSDA)
R2032 I2C(AVSCL)
U2000
YES NO
Check item(21). Check the I2C communication line :
Check GUI [U2800], VIDEO DECODER [U2000] and FET [Q2001] patterns as well as soldering.
If there is no problem, go to the next step.
Check the I2C communication line again after replacing the FET [Q2001].
If there is still a problem, the GUI [U2800] is faulty.
Replace with a new device.
The GUI [U2800] is faulty.
Replace with a new device.
Recheck from check item (1).
If it does not work, replace the PCB.
*The diagram shows an example.
(Signal patterns vary depending on the tim-
ing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- SCL frequency (400kHz normally)
Voltage scale : 1.0V/div
Time scale : 10us/div
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