garage door opener troubleshooting?

If there's a problem with the opener the default reaction would be to raise the door thinking someone is trapped under it. So the fact the door closes on you leads me to believe that the problem is with the door.

Most likely you have a broken spring, they are easily replaced by any garage door company. Check to see if you can open the door easily by hand, if not, it's the springs.

If you need a manual use the link below, Chamberlain mfg's Craftsman openers.

http://www.chamberlain-diy.com/doityourself/suppor...

Good Luck.

EDIT: If the door is heavy then have a garage door company look at it for you. A broken spring is not a do it yourself job. It can be dangerous if not properly trained and and have the correct springs and tools. Price can range from $170 to 200 from a reputable company and they check everything out including the opener for safe operation.

I just had the same problem. It was the springs (above the door the big coil spring on the metal bar that runs the length of the door. I replaced mine but you could try lubing it with some penetrating oil like WD-40. It cost me just under $500 with parts and labor to have a new one installed. Good luck!

You said the cables are tight, if you have a two car garage door look at the springs might have two springs if springs are good use WD-40 and spray the springs and all moving parts on the door Good Luck

check the electric eyes at the bottom of the tracks

check door is lifting straight look for anything binding the roller in the track

look for the sensitivity adjustments on the opener case

try small adjustments for less sensitivity

Richard has the best answer...

As far as your manual, they are all online now in PDF format. Just go to craftsman.com.