I have the same issue with my Sentinel LE V4. The speaker head on the end of the battery pack (Lite sound + 4-AAA Pack) basically just fell right off. I got it about a year ago and it has vaporized the blood of many a foe, so I am not too disappointed. I think I am going to use this saber as an opportunity to do it myself and learn a thing or two. It may be a cool idea to put together a sort of chassis to contain the electronics that will act as a shock absorber, though they already fit so snug. Anyway, I think it would be a cool project and have that custom I-did-this-sh*t feel

Edit: Just found there is a thread specifically for Chassis builds -
http://www.saberforum.com/index.php?topic=44766.0