Dispatched our Corona CA area technician to a restaurant for a second opinion on the state of their air conditioner. Our technician arrived onsite, checked in with management and proceeded to the roof. After obtaining all asset information the technician surveyed the systems. All units were in poor condition, no filters as they'd been removed and left on the roof. All condenser and evaporator coils were clogged. Units #1 and #3 are in the worst condition, rusted out and multiple failures. #2 and #4 have been repaired before. #4 was off due to a broken belt. Was able to get #4 up and running with a spare belt for now. Will quote all necessary work for the customer, including the replacements.