Without a circuit diagram or any test equipment it is almost impossible to fault these kind of boards. What you can do is make a careful visual inspection for any discoloured components; resistors, transistors etc. and replace them. This may fix the problem but then again it probably won't.
Some of the soldered joints look a bit iffy (but that may just be the quality of the photo'
. Retouching the joints with a soldering iron may cause normal operation to be resumed but then again it probably won't.
In my experience the best way of fixing a board like this is to first order the replacement. Then even the most trivial of home repair operations will see it working again.
Good luck, you'll need it, Colin