Black Screen on Android

I have built my game for Android and tested it on a few Samsung Galaxy devices. My game changes scene several times - from the Main Menu to the Game, from the game to a game over screen.

Most of the time, when changing to the game over screen, my screen goes black, and stays that way. From logcat, I can tell that the scene does load properly. With some lucky tapping, I can sometimes even return to the main menu.

From searching the forums, I've seen a number of suggested solutions, but none of them helped. I'm especially perplexed by the fact that logcat reports no clues, and that this problem does not always happen even inside the same build.

Can anyone offer any suggestions that might help me track down the source of this problem?