Audio silent after eyetube repair--what cable might be loose?

So the headset is working visually but I no longer have sound. I tried some of the obvious troubleshooting steps--making sure the output is set to the headset in both SteamVR and windows, deleting and re-scanning the entry in device manager, trying to update drivers, etc. But I must have clearly made a slip in repairing, and I'd just like to know what I need to do to make it right. Thanks!