The left channel of my Magnavox AZ9340 Portable Mini System stops working after I use it for certain amount of time (also have noticed that the time until it cuts out is getting shorter).

If I turn the system off for a few hours the left channel will work when it is turned on again.

At first thought it could be the amp or power switch but after switching speakers determined it was the left speaker.

Have never tested/repaired an audio speaker, appreciate any tips or suggestions.

Thanks

Ken