Denon AVR-X4500H - Page 109

YES
YES
YES
Check the I2C communication line. (HDMI Tx)
Check item(3-1.4.). 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 the
power is turned on?
IC391
TP53 I2C(CK)
TP54 I2C(DA)
HDMI Tx [IC431] is
faulty.
Replace with a new
device.
HDMI SW1 [IC391] is
faulty.
Replace with a new
device.
HDMI SW2 [IC381] is
faulty.
Replace with a new
device.
CPU [IC151] is faulty.
Replace with a new
device.
HDMI Tx [IC431] is faulty.
Replace with a new device.
Recheck from check item (3.1.)
If it does not work, replace the PCB.
Check item(3-1.5.). 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 next
step.
Check the HDMI SW1.
Remove the damping resistor
[R3914/R3916] of [IC391].
Is the "I2C" waveform correct?
Recheck from check item (3.1.)
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?
NO
NO NO
YES 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/div
Time scale : 10us/div
Before Servicing
This Unit
Electrical Mechanical Repair Information Updating
109