Maintenance Braselton. Did a leak check on all evaporator coils did not find any leaks. Blower wheels on all three are clean. Changed filters. Drain lines are clear. Found weak capacitors on the basement indoor unit and upstairs indoor unit. Changed both. Outdoor upstairs unit had a weak capacitor. Changed that as well. Pressures on all three systems are within range. All three systems are cooling at this time. Customer has black dust particles coming out of supply ducts. Recommend duct cleaning.