Make sure the trolley is not Jammed under the stop nut in the up postion. If so, back that nut off run the door down and turn the up limit counter clock wise until the door is in the desired up position.

I had the EXACT same issue just this morning. Opened fine but would not close and the same flashing light sequence. Door sensors wer perfectly aligned.
I did as doorguy suggested and found that yes it was jammed against the stop nut. After loosening the stop nut, the door went back down just fine. I then adjusted the up limit screw to ensure the door stops about 1" from the stop nut. It now works fine.

Wish it was that easy for me. Trolley is actually about 4 inches away from stop nut, back is starting to hurt from having to have to do actually physical exercise (rantings of an lazy 40ish male). When I press wall mount opener, you hear first click, then second click about 2-3 seconds later. Lights work fine on opener. If I unplug and plug opener back in, both lights on unit light and remain lit. If it is circuit board, is it worth replacing (cost roughly 70+ bucks), seen alot of complaints about plastic screws shredding, mine is perfectly clean, not a shaving to be found. Thanks again for any help.

JT

It sounds like your motor is locked up. To be sure you can loosen the chain and take it off the sprocket and hit the button and see if it runs. Otherwise I am sorry to say you may have to replace it.

Hello, I'm experiencing the same symptoms as JT2006. The opener will go up, but not down.

The trolley was tight against the stop nut, so I loostened the chain. When I hit the switch, the opener ran and pulled the trolley into the stop nut again.

I took the chain off the sprocket, pulled the cover off, and manually spun the motor down until the limit switch wasn't making contact. I hit the switch again, and the motor kicked in and ran in the open direction.

What is it that signals the motor to switch direction? Is there a sensor malfunctioning, or could the control board be failing?

johnsoer what you seem to be running into is a logic board that hasn't been satisfied that the door is open so it keeps trying to open the door. Remove that bolt and nut. On the side of your motor unit you will find a control marked 'up limit'. Use a small screwdriver and turn this control about 4 or 5 turns in the opposite direction of the arrow printed on the cover. You may need to do some further adjustments with the up and down limits because you removed the chain. A good thing to remember about this forum is to post first, remove and adjust last.

Thanks for the suggestion don_1. I tried that, but the opener still only wants to go up. A quick look at the logic board showed one sligltly singed connection where the solder isn't making good contact.

I'll try swapping control boards with my other (identical) opener and see if either of them work.

I have a 1/2 HP craftsman opener. About 3 weeks ago, I had to replace the nylon drive gear because the orignal one had been ground down to nothing. The opener worked fine for the past few weeks until tonight. I opener was running but wouldn't open the door. So, I opened the unit and discovered that the new drive gear has been stripped! Any ideas what would cause this? If I replace the gear again, what can I do to prevent it from getting stripped a 3rd time? One other thing to note, the green light on the back of the unit keeps flashing five times in a row, pauses and then flashes five more times. It is doing this continually.
Any help or advice would be greatly appreciated!!

Did you lubricate the new gear? Check your door. If your door is excessively heavy it will cause this. If your door is properly balanced and the springs are okay it will stay in place when you have it about waist to chest high.

I think the door is balanced and the springs OK. I checked it as you said and it did stay in place.
As for the lubrication, I think I did something dumb during installation of the new nlyon gear. The installation instructions said to apply grease generously to each tooth of the drive gear. I thought it was talking about the sprocket (that drives the chain) so that's where I applied the grease. Not on the nylon gear.
I'm not sure what I was thinking!
Would not having grease on the nylon gear cause it to become stripped in a few weeks of normal usage?

Absolutely.

About 80% of the time my garage door only opens half way. The other 20% it works fine. Do you have any suggestions?

I have a 1/2 HP Craftsman Model 139.53491SRT garage door opener. It's worked fine for the past several years when one day the "Travel limit" for the up position stopped working. I adjusted the "up adjustment screw" but when it opens it still doesn't stop until it hits the opener casting. I adjusted the screw "counter clockwise" and no change. I also tried to adjust it clockwise, but no change. Any thoughts as to what the problem is and how I could repair it? Thanks....

My craftsman garage door opener works from the wall switch but will not work with the remote. I bought a new remote and that doesn't work either. It is a new unit that has been in the box a long time.

I have a Craftsman 1/2 HP garage door opener, model 139.53962SRT1. For both the manual and remote controls, the door opens correctly and it starts to close properly, but it automatically opens again when it reaches the closed position. The light on the unit flashes when it automatically opens on its own. It will close when using the manual control if I hold the button down until the door reaches the closed position.

The symptoms are like there is something under the door that is keeping it from closing. I have used the door opener for several years and it was serviced about one year ago.

Model: 18473DM
It is new door opener. The light bulb was blinking when opens or closes, but OK at stable position. Now the light does not come on at all. The bulb is good. Any idea why?
Thanks.

This problem is very upsetting. After a wasting a lot of time, here is the answer. The instructions on the 1/2 hp Craftsman garage door opener to program the remote are WRONG. They say release the buttons on (both) the receiver and the transmitter when the light flashes. Here is the correct instruction downloaded from Sear's site, file:///C:/Users/ome/Downloads/L0303178.pdf: "1. Press AND RELEASE the "learn"
button on the motor unit. The
learn indicator light will glow
steadily for 30 seconds.
2. Within 30 seconds, press and
hold the button on the handheld
remote* that you wish to
operate your garage door.
3. Release the button when the
motor unit lights blink. It has
learned the code. If light bulbs
are not installed, two clicks will
be heard."

Holding down the learn button until the light flashes will never work.

Bought the 1/2 hp model 54985 chain drive from sears in Mexico. First unit never performed as stated. Stuck in open position and light flashed five times and could not correct it. Sears finally sent out their techs and guess what, they could not make it work after five hours of trying! Mind you this is brand new! We were given another of the same model to replace the new non working model. After three to four weeks this one did the same damn thing, stopped in open position and could not be reprogramed at all. This time i was told to bring in the faulty motor and Sears sent it off for repairs. Its back and we are not in Mexico but home in Arizona. So we have to wait to see if this unit works when we return in April. Mind you we bought this new on March 20th 2015 and warranty is one year. We return to Mexico after warranty runs out. Are we still going to be protected by Sears if this unit fails again? Sear never asked for the remotes just the motor so lets rule that out as a fix! So if you put your trust in sears....DON'T! I went to Costco to return a faulty pressure washer after two years and they gave me a full refund. No run around. Whats wrong with Sears, is management and no longer out to satisfy anyone but sears! I am a life long Sears buying fool and now i am not anymore! I have never in my life met with such resistance as i have with Sears! My recommendation, by any other unit but Sears and buy one that is stronger then the recommended model!