Have you joined the 20K volt club? I have, multiple times, I used to repair CRT and projection set televisions. Ever been popped by a flyback transformer?...
They measure the voltage by the inches of the spark. You want your heart jump started? 240 club is almost a joke, except that I hear 240 makes your muscles clinch up.. ☹️
You don't see the coils to find issues nitwit, you use a multimeter and/or an oscilloscope. Shit can and definitely does fail internally where your eyes can't see.
That's the whole reason they make advanced testing equipment. pLEaSE sToP BOthErINg mE!
Outside is corroded from years of humidity means inside is corroded from years of humidity as well. How much? Who the hell knows? Fuckit, let's just plug it up and cross our fingers...
Or maybe, just maybe, use a little lick of sense and at least open it up and look inside first. Fuck, at least look first, not like it's rocket science to use a Phillips screwdriver to open the cover...
When I see corrosion, I don't trust where electricity goes. This is just common fucking sense to anyone that understands squat about electricity and values their life.
Hell, even if the outside of the thing is perhaps only 3% corroded, the inside could be 33% corroded...
Nobody knows unless they at least inspect it to start with. I mean hell, I've dealt with flooded cars before, you know how many of those are outright deceiving and totally ruined internally and go to scrap?
It's not hard to check inside of a guitar though. Is there something wrong with at least checking and cleaning it up first, inside and out?