Genie Garage Door Opener Problem

[Doug Dodge]

I have a Genie Stealth, belt drive, garage door opener that is about 10 years old. Recently, it has been acting up. When I push the button to open or close, the motor unit will click, but do nothing. It doesn't seem to matter whether I'm using the wall button or a remote. Sometimes, if I release the door from the carrier, then press the button repeatedly it will begin to work. It may then work once, then stop again, or it may work properly for several days. Anyone have thoughts on what to check ?