There are a couple companies with websites that say they can get parts for these openers. Search for Stanley.
IMHO it is an inferior GDO (I used to have one) and it does not have the latest safety features. I suggest replacing it with a Genie screw drive model that you can get at a home center.
When you repair or replace it, install a single output surge suppressor on the outlet before plugging it in. Belkin sells one for about $10. It won't save it from a very near lightning hit but will save it from line surges. I suggest using these on any appliance that has electronics inside. Warranties don't cover "Acts of God".