garage door opener malfunctioning

[mcf57]

I'm having an issue with my garage door opener when closing it. Its a Sears Liftmaster (at work and not sure of exact model) from about 1999. Last few weeks, it would close to about the middle, but then stop and reverse/go back up. I would hit the remote switch again to stop it. Hit it again and it would usually go all the way back down. This morning, it would "attempt" to open, but get a few inches and stop. I had to then manually release the opener from the door and then open the door manually. I thought it was the chain and tightened that a few weeks ago, but did I maybe mess it up somehow when doing this? Any other suggestions on what else might be going on and/or wrong here? Also, while its not attached to the door, it goes up/down fine so I'm thinking it has to do with the tension. Also, no obstruction between the sensors.

[remeizo]

A few things to try

If you have not had this issue fixed yet here are a couple possible causes and fixes. It is possible that since your opener is a chain drive from '99 that the gear is wearing out or has completely worn out. You can get a new gear from sears and replace it yourself if you would like. One way to tell for sure if it is the gear is to pop open the cover and look for a bunch of black dust (metal) on top of the white nylon gear or to look for white nylon chips all over inside of the opener. Those gears go out almost like clockwork at the 12 year mark. If it is not the gear and sprocket assembly then you can try to mess with the force adjustments on the opener and see if it will get through where it thinks it needs to reverse because it thinks it hit something. Changing out the gear and sprocket isn't the easiest task. The kit will come with a worm gear and usually you will not have to change that out unless you notice a large amount of wear on it. That is a pain to change and can add about 45 extra minutes to the repair in some cases. I can change a gear and sprocket in about 20 minutes but of course I do it all the time!

[HayZee518]

door travel

openers have three items to look at. first is the up travel limit, 2) the down travel limit, 3) a down travel current relay. when the door hits something traveling down, motor current rises. the relay is set for a certain "amps" before it operates and reverses the door motor.

[tmordoor]

Sounds like either the photo cells are misaligned or the sensitivity needs to be tweaked up a bit. A little lube on the drive chain wont hurt either!!