TNS510 Head unit not playing audio

[mk1]

Hi

Has anyone ever had an issue where their Toyota TNS510 head unit does not play audio until about 15 mins into the journey? The telephone works fine and all the buttons beep when you press them. I have tried playing the radio, cd and from the memory stick but I don't hear anything until for about 15 mins then all of a sudden it starts playing as normal.

Any help would be appreciated.

Thanks