It's been acting up lately, sometimes it works fine and other times it doesn't work at all. Sometimes it opens and closes only partially? Now it only works when I unplug it and plug it back in, but only works once! I've checked all the wires and sensors and they are good.
Verifying that the door operates correctly and without excessive force with the opener disconnected is a required first step. If the door jams, the opener cannot be expected to work well.
Given a mechanically sound door system that operates properly by hand, odd behavior in "modern" (25 years or less, perhaps) garage door openers is almost always a sign of "time to replace the logic board."
It's actually a slightly fraught choice, since a logic board is typically 1/2 the price of a replacement opener, and the replacement opener comes with a warranty, while the logic board often does not, and there's always the possibility that it won't fix the actual problem.
That said, I've replaced one and it did cure the problems that opener was having (which were life-threatening and probably resulted from a nearby lightning strike - I also added a surge suppressor to the outlet.)
My Craftsman GDO (date of manufacture November 2013) also worked intermittently after about a year of service. It opened or closed partially and the power went out. (lights went out on the unit and the LED on the controller went out) If I tapped on the motor unit the power was restored. I took it apart to try to locate a bad connection. This sounds crazy but after disassembling and reassembling the motor unit several times, I found that it worked without the light bulbs but as soon as I reinstalled the bulbs the problem returned. Probably my last Craftsman GDO.
I had intermittent problems from my house to my detached garage . It seemed that when it got colder the problem worsened . I think the logic board gets weak picking up the signal after a few years . I took a wire coat hanger and opened it up to make a triangle and taped it to the antenna on the unit . It has been working for two months now ! I just gave it a better antenna instead of changing the logic board !
I FOUND THE FIX FOR MY INTERMITTENT SEARS 139 OPENER PROBLEM.
On the RPM board, the black, U-shaped case on the RPM opto-isolator sensor was slightly loose and just pressing the case one way or the other caused the opener to work or fail. Apparently the loose case was interrupting the optical path. I pressed the case to where it worked, added a dab of glue to hold the case in place and presto, fixed it. Haven't seen this fix posted anywhere yet. Lived with this problem since new, six years ago...