Denon AVR-X4400H Service Manual

Also see for AVR-X4400H: Manual Owner's manual

YESYESYESCheck the I2C communication line. (HDMI Tx)Check item(9). Check the I2C communication line :Check the CPU.Is the "TP53, TP54" waveform of the TP near the HDMI SW1[IC391] correct (like the one shown in the diagram) when thepower is turned on?IC391TP53 I2C(CK)TP54 I2C(DA)HDMI Tx [IC431] isfaulty.Replace with a newdevice.HDMI SW1 [IC391] isfaulty.Replace with a newdevice.HDMI SW2 [IC381] isfaulty.Replace with a newdevice.CPU [IC151] is faulty.Replace with a newdevice.HDMI Tx [IC431] is faulty.Replace with a new device.Recheck from check item (1).If it does not work, replace the PCB.Check item(10). Check the I2C com-munication line :Check HDMI SW [IC381 or IC391],HDMI Tx [IC431] and CPU [IC151] pat-terns as well as soldering.If there is no problem, go to the nextstep.Check the HDMI SW1.Remove the damping resistor[R3914/R3916] of [IC391].Is the "I2C" waveform correct?Recheck from check item (1).If it does not work, replace the PCB.Check the HDMI SW2.Remove the damping resistor[R3812/R3814] of [IC381].Is the "I2C" waveform correct?Check the HDMI Tx.Remove the damping resistor[R4326/R4328] of [IC431].Is the "I2C" waveform correct?NONO NOYES YES YES NO*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/divTime scale : 10us/div108Caution inservicing Electrical Mechanical Repair Information Updating