Stereo wont turn on/off with ingnition?

[Brad_182]

Recently on start up, my stereo has not been turning on, this means when turning off the ignition and exiting the car, i am leaving the stereo on (
Any thoughts on why this has started happening? it seems as if after about 20-30 minutes of having it on, it beeps, and then turns itself off.

Any help would be greatly appreciated

Thanks