Marantz SR6006/U1B Service Manual page 90

DDC_CLK/DDC_DATA/TMDS : Check items (17)/(19)/(24)/(32)
TMDS Waveform
Timing waveform illustration from the start of CEC3.3V to when reset is released : Check items (22)
CEC3.3V
338ms
3002_RESET
Controlled waveform(I2C), when power is turned on : Check items (23)
HDMI_SCL
HDMI_SDA
POWER ON
0.9V
DDC_CLK
2.48V
DDC_DATA
90