LOL
Not to discourage you but most of the time there's no way you can tell if it's repairable.
Even the meaning of the word "repairable" is subject to discussion: as long as the board isn't the one and unique known in the world you can pull parts from an other board.
To me unrepairable means a custom chip is faulty, and again there's no way to tell before you actually start the repair. A bad RAM, ROM, TTL or custom chip can all have the same symptons.
I have lots of non-working PCBs and if I knew if they were repairable it would mean I know what's wrong with them and if I knew what was wrong with them they'd be fixed already.