Malfunctioning Garage Door Opener

We take many of our modern conveniences so for granted that we hardly realize they are there until they malfunction. Our “AccessMaster” garage door opener for the north stall is a prime example. It has worked flawlessly for the last 10 years or so but now has problems with closing. It opens the door very normally with the switch or remote. When the switch is touched with the door up, it moves the door a few inches and then reverses back to a fully opened position and the light flashes 10 times. I have assured that the sensors are properly aligned and unobstructed and have pulled the emergency release cord and  able to manually move the door up and down without any obstruction. I mentioned that the touch plate switch in the garage opens the door normally and if the plate is not just touched but “held engaged”, the door closes without incident. When the door is open, the remote only causes the light to flash the 10 times. We can live with it under these conditions but need to get it fixed. Any ideas would be appreciated. I am not aware of any Garage Door service here in Seward. Years ago we did have a company from Lincoln do some maintenance while working on construction here in town. The knowledge to resolve this problem appears to be beyond my grade level.