How did static charge ruin my control board?
Measure the protection diodes - 3 pins marked with A7, first. The one measured with low resistance, needs to be desoldered to measure it correctly . If the resistance is still low, you have to replace the opamp LM324. If you're lucky, then it should work with removing the diodes.

You would need a hot air gun and some skills to desolder/solder components without damaging the board.

EDIT:

More likely it's the input capacitor that is damaged.