Lost signal while using Xbox 360...dips to black

SOURCE: No video throught HDMI output

press set up go option number 1 then go hdmi monitor and input yes. then press set up again

SOURCE: HDMI sound?

i am new at this, as i just got a receiver with hdmi ports as well. but the receiver will not transmit audio through hdmi, you have to use either the optical cables, coaxial inputs, or the rca red and white inputs.

SOURCE: new home theater setup- no signal at tv using onkyo tx=sr605

This might somewhat help. Today I went back .. I went HDMI out of the Cable box and DVD player into 2 of the TVs HDMI ins. The digital audio out from each, straight to the receiver and things are working ok. All speakers are working OK. Sound isnt as loud or crisp but unfortunately I found no other solution.

SOURCE: Onkyo TX-SR606 getting no sound from HDMI sources

Not sure if this is your fix, but I had what I thought was the same problem. I played with my Onkyo quite a bit ensuring the correct assignments for HDMI, audio and all that stuff. Turns out I neglected to make sure the output devices were properly assigned. Many devices aren't default to output sound over HDMI. I changed the audio out settings on the cable box to HDMI and suddenly the Onkyo worked great. I know, I'm an idiot for not checking that in the first place, but maybe someone out there is having the same trouble as well.

SOURCE: Picture sound blackout (blink) when cable box/receiver HDMI used

Onkyo service told me, the second timethat I called them, that there is a known HDMI handshake issue with Motorola and Atlanta Scientific cable boxes. The only solution, and it was a solution, is to connect the box through the HDMI 1 port ONLY. All the other (2,3,4) result in blinking/dropping of signal. I did this, changed the cable/satelilte setting to HDMI 1 and all is well.