First pop out the controller and place it back. This could be a Power supply problem.
This can be caused by corrosion under the jumpers. Locate the IRQ pin stack on the printed circuit board. There should be jumpers on three of them From top to bottom 5 all the way to the right , 8 all the way to the left, 9 all the way to the right. The jumpers must be in that position. If they are in that position, Take them off and replace them exactly as they were.
If you have a spare controller, put it in and if the problem remains it is the power supply board. It could be the controller or the power supply.