I got a free Mac Classic some time ago, and on my quest to clean the garage, I have decided to fix it up to add to the collection. I glanced at the board for bad solder joints, but didn't find anything. Just to be sure, I freshened the solder on the connector to the deflector coil, still no improvement.

What should I do next?

If you look really close, you see a fine horizontal line in the middle of the screen.