I found Open Fields vs Bad Fuses or Switches. From The size of the Yard, I feel the Blowers were Challenged (Distance & size).

I am unfamiliar with the B&D leaf blowers. Is your 500 leaf blower a gas powered or an electric leaf blower. The trouble shooting would be entirely different.

If gas and assuming you have maintained the leaf blower, the first thing I would do would be to run a carburetor cleaner either using a cleaning solution that is added to the gas tank or a solution that you spray into the carburetor. If that did not work you may have to take the carburetor apart and do a through cleaning.

If electric look at a failing battery and loose wires in the electrical system. That failing it may be necessary to take it apart and clean the insides. Look for dirt in the contacts, bad bearings, etc. I have an electric drill that ran slow and eventually quite. I have taken it apart and every thing seems to turn freely, but when reassembled will not turn over.

If you can not find the problem yourself there is no need to take it to a professional. In my experience, IF they will look at the unit, the cost of labor will run more the the cost of a new unit.