Denon AVR-X3300W Service Manual page 87

Checking the reset waveform. (HDMI Switcher1)
Check item(10). Checking the reset waveform :
Check the waveform.
Is the "RESET" waveform of the TP near the HDMI Switcher1
(U1003) correct (like the one shown in the diagram) when the
power is turned on?
RESET
U1003
YES
Check the I2C communication line. (HDMI Switcher1)
YES
Check item(11). Check the I2C communication line :
Check the CPU.
Is the "P_DA, P_CK" waveform of the TP near the HDMI Switch-
er1 (U1003) correct (like the one shown in the diagram) when
the power is turned on?
P_CK
P_DA
U1003
*The diagram shows an example.
(Signal patterns vary depending on the
timing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- SCL frequency (400 kHz normally )
YES
HDMI Switcher1 (U1003) is faulty.
Replace with a new device.
YES
Recheck from check item (3).
If it does not work, replace the PCB.
Check the HDMI Switcher1
Remove the damping resistor
R1170/R1169
Is the "I2C" waveform correct?
Examples of confirmation waveform
HDMI Switcher1
NO
(U1003) is faulty.
Check the reset circuit between
Replace with a new
CPU (U1018) and HDMI Switcher1
device.
(U1003).
If there is no problem, the HDMI
Switcher1 (U1003) is faulty.
Replace with a new device.
Recheck from check item (3). Recheck from
If it does not work, replace the If it does not work, replace the PCB.
PCB.
NO
Check item(12). Check the I2C com-
munication line :
Check HDMI Switcher1, 2 (U1003 or
U1000), HDMI Tx (U1001) and CPU
(U1018) patterns as well as soldering.
If there is no problem, go to the next
step.
87
NO
Check the HDMI Switcher2
Remove the damping resistor
of U1003. (R1061/R1062) of (U1000).
Is the "I2C" waveform correct?
YES YES
HDMI Switcher2 HDMI Tx (U1001) is
(U1000) is faulty. faulty.
Replace with a new Replace with a new
device. device.
check item (3).
NO
Check the HDMI Tx.
Remove the damping resistor
(R1974/R1975) of (U1000).
Is the "I2C" waveform correct?
YES NO
The CPU (U1018) is
faulty.
Replace with a new
device.