Not been playing the guitar for years. Forgotten all about it until one day I decided to have a go again. But discovered I had left the AA batteries inside and it the battery compartment had been swimming in alkali cos of battery corrosion. Saw your post here and decided to have a go at fixing it. Can I know how do you tell that the capacitor is due for replacement and also, can the red wire be directly soldered to the positive end of the battery connector lead?