fisher gold bug

Anyone have any tutorials on repairing a Fisher Gold Bug? I have one that I took to an abandoned island a while back to search for a weatherproof light I had lost. I found my light, but in the transit to the island the control box got splashed on. It still detects metal properly but the audio...

so this is my second hunt with a fisher gold bug at the beach (dry and wet sand). what i can say is that the machine do pretty well and i have been rewarded with some lovely old and new Chinese coins. for the video hope you like it and next time i will try to be more organised. cheers