How do you clean the fans in a Runco (CL 810) projector?

I've worked on many, many types of projectors over the years, although not this particular model.  The obvious question is have you cleaned the filters? Every projector has at least one main intake filter.  Beyond that, I can assure you that once you open the case, an interlock will engage to cut power to the unit.  You'll need to locate and bypass that interlock switch before you can visually assess whether all the fans are indeed operating correctly - most DLP/LCD type projectors have numerous fans, many of which are enclosed 'squirrel cage' types.  You'll encounter many, many wiring harnesses and ribbon cables and you may need to remove the main circuit board to access the buried fans in the unit - they can be replaced, but cleaning rarely lasts all that long as the fan bearings fail.  In all, unless you're fairly competent with complex electro-mechanical assemblies, you may want to take the unit to a technician to have it looked at.