When done cleaning, place the circuit board back in the plastic housing.

The scroll wheels should be facing the housing with the logo and labels, and should slide onto the 4 screw holes.

Make sure the plastic headphone jack brace is in position.

Position the wire in the slot on the other side of the amplifier, it should slide down onto the housing and become fixed.

Close the housing with the other plastic half. It will click into place.

Replace the 4 screws using the #6 torque screwdriver.