Marantz NR1509 Service Manual page 88

Check the I2C communication line.
YES
Check item(15). Check the I2C communication line :
Check the CPU.
Is the "I2C" waveform of the HDMI OSD [U1030] correct (like the
one shown in the diagram) when the power is turned on?
HSCL
HSDA
U1030
YES NO
Check item(16). Check the I2C communication line :
Check HDMI OSD [U1030], CPU[U1013] patterns as well as soldering.
If there is no problem, go to the next step.
Remove the damping resistor [R1622/R1606]
of [U1030].
Is the "I2C" waveform correct?
YES
OSD [U1030] 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
timing.)
Points for checking waveforms
- Crest value (3.3V normally)
- Signal change
- SCL frequency (400kHz normally)
Voltage scale：1.0V/div
Time scale：10us/div
NO
The CPU [U1013] is faulty.
Replace with a new device.
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