The previous time I've come across this was with a Fender Concert and then I
put it down to someone previously soldering a component with the "active"
board in situ and had burnt part of the grounded whale-hide sheet
underneath. Placing some extra insulation cured that time also. So anyone
know precisely what the failure is . Presumably taking up humidity but what
next? salts in the material forming a conductive path in the core of the
material. I will try a megger on the material when I next get to the amp ,
no problem seen on external surfaces with a 30M DVM. And what is that stuff?
whale-hide? artificial leather ?