Disconnect all of the wand attachments from the unit.
Remove all of the clear plastic holders. There are a total of seven screws to remove, and three plastic holders.
Flip the unit on it's face, with a soft towel under it. Remove ten screws, all on the outer edge of the bottom of the unit. To keep screws together, and with the correct piece of the unit, try to use scotch or masking tape them on a strip of tape and tape them directly to the portion that you removed
Gently pull the bottom, with its back facing up, outward and down to the floor, as to not disturb the connected wires, which are not long enough to pull straight downward.
Look over all of the hoses, their connections and the filters inside each end to make sure there are no holes, cracks or kinks in them. Make certain that the hoses are tightly connected to each port and there is not a leak. Inspect the filters for clogs, too much dust or tears.
Replace any bad hoses or connections. If the end of each hose is bad, simply cut the tip of it off and put it back on it's port. Throw away dirty or clogged filters, and replace them with new ones. To be safe, use either electrical or duct tape around the filter housing of each, to prevent air leaks or separation of the housing.
Check the interior for any debris or dust blocking the fan and fan motor and simply remove it or clean it out. Check for loose wires, bad connections or wires that are damaged.