Denon AVR-X2300W - Page 103

Check item(55). Checking the reset :
Check the CPU.
Is the waveform of the TP near the GUI(U1026) correct (like the one
shown in the diagram) when the power is turned on?
Check item(56). Check the I2C communication line :
Check the CPU.
Is the "I2C" waveform of the TP near the CPU(U1018) correct (like
the one shown in the diagram) when the power is turned on?
Check item(57). Check the I2C communication line :
Check GUI (U1026), HDMI SW(U1103) and CPU(U1018) patterns as well as soldering.
If there is no problem, go to the next step.
Check the CPU.
Remove the damping resistor (R1493/R1494)
of (U1018).
Is the "I2C" waveform correct?
The CPU(U1018) is faulty. Replace with a new
device.
Checking the reset waveform.
Check the I2C communication line.
10ms
10ms 10ms
Example of the waveform to be checked
The GUI (U1026) is faulty.
Replace with a new device.
The GUI (U1026) is faulty.
Replace with a new device.
YES
Recheck from check item (1).
If it does not work, replace the PCB.
Check the reset circuit between CPU (U1018) and GUI (U1026).
If there is no problem, the GUI (U1026) is faulty.
Replace with a new device.
NOYES
*The diagram shows an example.
(Signal patterns vary depending on the
timing.)
Points for checking waveforms
- Crest value (3.3 V normally)
- Signal change
- SCL frequency (400 kHz normally )
NO
YES
YES
NO
103
Caution in
servicing
Electrical Mechanical Repair Information Updating