Ralph

Hi... I have a laney rb4 that just started acting funny..... While i was performing everything was fine and then it suddenly wouldnt produce sound from its own speaker..... The lights are on and everything.. But sound from the speaker cuts out and it just goes silent until i switch it off and on again..then it cuts out again... But it sends sound to the mixer without a problem.... But its internal speaker just dies out midplay.. Plz help..