Clean unit, especially fan blades.
Inspect pulleys, belts, couplings, etc.; adjust tension and tighten mountings as necessary.  Change badly worn belts.  Multi-belt drives should be replaced with matched sets. 
Perform required lubrication and remove old or excess lubricant.
Clean motor with vacuum or low pressure air (less than 40 psig).  Check for obstructions in motor cooling and air flow.
Remove tags, start unit and check for vibration and noise.
Clean surrounding area, record results and findings and report any needed repairs or operational adjustments.

Obtain and review manufacturer's instructions.  Follow manufacturer’s instructions or procedures if different to these instructions or procedures.
De-energize, tag and lock out fan motor disconnect.

Standard and Phillips head screw drivers-various sizes; Pliers-vise grip (2), slipjoint, needlenose, diagonal; cutting pliers, side cutters; Ball peen hammer; Hack saw and spare blades; 3/8' drive socket set and ratchet; Small set of Allen wrenches; Assorted center punches, drift punches, and steel chisel; 12' measuring tape; Crescent wrenches 4" to 8";  Open and box end wrenches ¼" to ¾"; File; Pipe wrenches to 14"; Small level and square; Pocket knife; Flashlights; Grease guns and oilers; Wire brush; Extension cord and inspection lights; Various cleaning tools - brushes, scrapers, etc; Emery cloth.
Vacuum
Cleaning materials
Lubricants
Gloves.