On the other hand, if you can find the problem yourself, most boards can be fixed for a few dollars worth of parts. I'm not very experienced with diagnosing PCB's myself, but I'm pretty good at asking questions, lol. I read a lot of repair logs when I was trying to find the audio problem with my Super Punch-Out board and it seemed like the vast majority of board issues can be diagnosed and fixed with a selection of under-a-dollar TTL logic chips and a $20 logic probe and/or asking the right questions. A 90 cent TTL logic chip turned out to be the problem with my board.
Read the repair logs at MikesArcade.com and see what a wide range of problems those damnable TTL logic chips can cause when they go bad.