I think you repaired my dead sub many (~7) years ago. Part of the repair was to add a fan to help cool it. Now, when I start it up after it has been off for a while, the fan squeals for a bit, then stops. I thought I would ask you before I tore into it: what kind of fan did you put into the sub for cooling? It is something I can easily replace? Do I need any special tools. Unfortunately, I tossed all the old emails, so I could not ask you directly.