Dispatched our maintenance technician to a Bakersfield, CA, restaurant, to perform regularly scheduled services for both their HVAC and refrigeration equipment. Bi-annual minor visit including inspection off all equipment and filter changes on the air conditioners. While completing the service, our technician found a VFD cooling fan that was vibrating badly. Functional but will recommend to replace before it fails. Also recommend replacing a belt on the exhaust fan for the kitchen.