Stereo player losing power
 

Hi

I've recently bought a 1995 Mazda 323F GLX (very good condition too!) following the tragic destruction of my old car. I managed to salvage my old cd player/stereo (ripspeed) and install it into the Mazda but I've noticed once you switch off the engine the cd player loses all power (which is really annoying for tuning the radio stations as it won't save the presets without power). I've also noticed in the last day or so that even while driving the stereo intermittently loses power then comes back on again. The connections seem fine, it's not the battery (lights remain fine as it does it) but does anyone have any ideas or suggestions I could look into?

Cheers