I have no audio coming out of the speakers since 5 days ago. I did the firmware upgrade, but the subwoofer still doesn't power up. Outlaw support thinks it's a problem with the 12V trigger, but is it at the speaker end or the receiver end? Any ideas how to trouble shoot this? (I get sound from attaching a separate speaker directly and from plugging in headphones, so it's the sound via the subwoofer connected to the speakers that is the problem).

What's your wiring arrangement? You mention the subwoofer is connected to the speakers, so I'd be particularly interested in that portion of the wiring.

Here are some thoughts: if you have a pair of computer speakers lying around, you can place them on the pre-amp outputs instead of the amp. This will allow you to test the behavior of the pre-amp outputs themselves. You can also try to remove the 12V trigger from the equation between 970 and amp by completely removing the trigger cable and manually turning the amp on. I'm not sure if either of these are applicable for your case, but they're some ideas.