trinity sound problems

[gee man]

Hi folks

I've got a korg Trinity pro have it about about 22yrs now still gigging it. but the last couple of gigs there has been a crack and pop sound coming from it. Quite a loud bang sound off sorts which is pretty bad. I haven't a clue really what it is don't think it's mains issue though. Would it be dry joint ?

Has any body experienced this or have an idea

Thanks