oswellm

In trying to unlock the volume I have really screwed my travel partner up! I must have changed something in the menu not seeing it the screen as it was dark so the sound became just a buzz. I formatted the disc from the onscreen menu, restored factory defaults and now cannot gain access to the service menu. I initally found it difficult to get in (and should have left it alone, I know). I used MP3 filemanager to put an album but it is not playing. Nothing in the service manual as far as I can see. 1) are there any tips on entering the servise menu rrllrlrlud I should know. 2)Is there a master reset? Before you say "idiot", I've already said it and "it" and much worse