There can be damage to the coil if you remove the cover carelessly. If the coil gets snagged by the solder joint burr or jabbed with a screwdriver when trying to get the cover off, there can be extreme damage to the coil or coils. Make sure the connecting wires from each bobbin didn’t get snagged or pulled and check to see that the solder joints from the cable didn’t get pinched or broken. Make sure the hot wires don’t short out with the ground. Breaking one turn of magnet wire on a coil will make the pickup inoperative.