No sound just video
Okay, a couple of things.
This speaker issue seems to be a common problem, and I believe it most likely occurs due to rough handling of the unit. Although it seems to be fairly rugged, it should be treated gently. In general, I would only handle it as much as needed, and be careful when setting it down, and make sure it doesn\'t get dropped.
With that being said, the unit can be opened, however doing so will break at least some of the "snaps" that hold it together. If it is out of warranty and you need to get into it, this is a necessary evil.
Step one: Remove the battery cover (one phillips screw) and battery. There is a second, smaller phillips screw that also must be removed.
Step Two: At this point, you are ready to separate the unit. Using multiple flat head screwdrivers, pry the unit open (starting on the right side when looking at the unit from the front) then "wedge" the pried open area with a second flathead screwdriver as it will naturally want to close back up. Continue working your way around the unit, being careful not to crack the screen. You will break some tabs along the way, but I see no way around this as they are not visible to try and release them any other way.
Step Three: Once you have separated the two halves of the unit, the power button will have fallen out. This is okay as it will slot back into place when you reassemble the unit. Just set it aside and do not lose it.
Step Four: I do not know the exact failure mode of the speaker, however you will find that it is apparently strongly secured in the housing with an adhesive (epoxy or some sort of resin) and if you had to remove it it would be difficult and not very fun.
MY SOLUTION: I hooked the battery back up and turned on the music feature, which should play music from both the camera and the parent unit. In my case, I found that tapping hard on the speaker (it took more force than you would think) would cause the music to momentarily play. I found that wedging a screwdriver between the plastic housing and the speaker body would make the speaker play. I used a small nail (like a trim nail for small trim) and wedged it between the speaker and the housing, then trimmed off the excess of the nail.
This solution is not ideal, but it was relatively quick and worked to keep the unit functioning for now. I imagine that there is some sort of connection that has failed internally in the speaker, and that wedging it has (at least temporarily) reformed the connection. I imagine that a new speaker could be installed with some work to remove the old speaker, and then a new one soldered in and glued into place.
Once I got the speaker working, I disconnected the battery and carefully replaced the power button, then the two halves simply snapped back together. I replaced the screws and reinstalled the battery, and all has been working as it should. The case does show some damage from my prying, and it doesn\'t fit as tightly as it used to with the broken snaps, but it does hold together and doesn\'t have any issues in normal use.
In all, it certainly beat buying a whole new unit, especially since it was working just fine other than the sound. Good luck!