No AC found only one unit working properly, back hallway. Front lobby unit had a bad condenser fan motor, replaced motor, system is cooling. Conference room and hallway next to it are zoned together, main thermostat had failed, replaced thermostat, checked operation, hallway/conference room cooling fine. While here I did as much maintenance as I could, replaced capacitor on conference room unit that was about to fail, cleaned electrical compartments, washed condensers, flushed and vacuumed drain lines checked charge on all units, during this time I discovered the North Hallway unit was not cooling, traced problem back to indoor unit, by this time of day attic temps were dangerously hot, decided to come back Friday morning to fix this unit. Other three units are cooling great 7/5 returned and found bad control board on North hall unit, replaced board, checked operation, system is cooling Every unit is cooling except server room unit, its been down for several years. All units washed,