We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
There is a problem with many third party audio adapters in that they're wired to identify themselves as a full AV cable to the Xbox 360. The original audio adapter which is no longer in production, was wired to have its own unique identity.
So in a nutshell, the Xbox 360 thinks it's supposed to be sending composite video over the AV output, not just audio.
And this highlights a limitation to how the Xbox 360 handles video output. For technical and some licensing reasons, it cannot output HDMI and analog video at the same time.
When the Xbox 360 boots it prioritizes HDMI and tries to establish a connection with the receiving device. If there is no response, it instead checks if there is anything connected to the analog AV port and if so, switches over to analog video output. If nothing
is connected to the analog AV port, or a properly wired audio adapter, the Xbox 360 simply keeps on waiting for the HDMI connection to establish.
The same thing happens if the communication over HDMI is interrupted. If there is nothing connected to the analog AV port or a properly wired audio adapter, the Xbox 360 waits for the HDMI connection to re-establish. If there is an analog AV cable connected,
it reboots so that it can configure itself for analog video output.
To solve the problem, you either have to crack open the audio adapter's connector and re-solder it to make it identify itself as an audio adapter, not as an AV cable. If you have a soldering iron and want to take a crack at this, you should be able to find instructions
on the net for which pins to wire.
Another soloution is to try getting hold of a used original audio adapter, or a third party one that is known to be wired correctly.
Of course the most dramatic and expensive solution is to get an Xbox 360S. As stated by Bill Gates in an interview once: "Microsoft has never been accused of not knowing how to make money". :P