What's wrong with my garage door?

[Hawkmoon]

Single car garage. Sears door opener that has been in place and working fine for more than fifteen years. It's not the main garage, so it doesn't get used daily, but it does get used -- more in the summer when I need to access lawn and garden equipment.

Recently it has decided that it doesn't want to stay closed. It runs all the way down, but when it bottoms out it immediately opens again. I've verified that the safety lights are working. I've swept cobwebs away from the lenses. Last week I gave a good sweep to the touch-down line, thinking debris might be tripping the sensor. That worked last week, but today it doesn't work. I have turned the DOWN limit screw to the farthest extent it can be turned, and it didn't help.

Before I drill new holes and move the bracket farther down on the door, is there anything else I should try?

[Devonai]

Check the IR sensor alignment.  The receiving sensor should have a green and red LED.  If you've got a good signal, the green will be lit.  If not, it'll be red.  If you get a red blinking LED, that means there's an obstruction.

[Hawkmoon]

Already checked that.

I think I have a bad down-travel limit switch. If I turn it all the way counter-clockwise, from the full up position the door barely starts down before it stops and reverses. If I turn it maybe 1/8 of a turn, I get a little more down-travel before it reverses -- but nowhere near closed. Another 1/8 of a turn, and the door goes all the way down, slams to a stop, and reverses.

I doubt the switch is available, now that Sears has gone belly up. (And I doubt I can find the instruction manual with the parts list anyway.) Is there any possibility that spraying the limit switch with electrical contact cleaner might bring it back to life?

[Jim147]

I'm sitting outside your house pushing a button. It funny.   

[grampster]

Jim 147 wins the thread today.

[Regolith]

I doubt the switch is available, now that Sears has gone belly up. (And I doubt I can find the instruction manual with the parts list anyway.)

searspartsdirect.com is still operating. I've been getting parts from there to keep our Craftsman lawnmower limping along. Might be worth a try.

[Brad Johnson]

First make sure there's no debris under the door, then make sure your safety beam is working properly first, then adjust the position limiter, then tweak the force setting.

Brad

[Hawkmoon]

First make sure there's no debris under the door,

Done that

then make sure your safety beam is working properly first,

Done that

then adjust the position limiter,

Doesn't adjust. It jumps from only closing about a foot when the down limit switch is set full counterclockwise, to closing all the way and reversing open when I turn the adjuster screw just over 1/8 of a turn.

[K Frame]

My guess is that with the model and serial number you'll be able to figure out who made that opener for Sears and you'll be able to get the switch you need from the manufacturer.

[Brad Johnson]

My guess is that with the model and serial number you'll be able to figure out who made that opener for Sears and you'll be able to get the switch you need from the manufacturer.

Most Craftsman garage door openers were made by Chamberlain.

Brad

[K Frame]

And Chamberlain is still in business and selling parts.

[charby]

My 14 year old Chamberlain/Craftsman did that last winter, had a wire break on the limit switch, a got the soldering iron out and replaced the broken wire. There is 2 or 3 wires that move with the switch IIRC.

[Doggy Daddy]

What's wrong with my garage door?

Is the door installed in a pay wall?

[K Frame]

Is the door installed in a pay wall?

 

[Ron]

Have you tried rebooting it? 

It has to be the limit switch IMHO.

[Hawkmoon]

Thanks to Regolith's link to Sears Parts, I found a Sears video that addresses problems with their door openers. It didn't tell me how to fix the problem with mine, but it did lead me to think that what I believed was up- and down-travel limit adjusters is actually up- and down-travel force adjusters. The travel limit switches or whatever must be hidden inside somewhere, which means I need to move a bunch of schmempf out of the way so I can lower the power head and open it up for a look inside.

[Ron]

Usually, I see limit switches at either end of the track that the arm holding the door runs back and forth on.

One to set the closed position near the door opening and one to shut it off when opened all the way, near the unit itself.

Generally they are just low voltage micro switches that the base of the arm will actuate when coming in contact with the switch.

[charby]

Usually, I see limit switches at either end of the track that the arm holding the door runs back and forth on.

One to set the closed position near the door opening and one to shut it off when opened all the way, near the unit itself.

Generally they are just low voltage micro switches that the base of the arm will actuate when coming in contact with the switch.

Mine were under the metal cover that came off with 6 screws IIRC. I did my repair with the opener hanging from the ceiling.

[Brad Johnson]

Depends on the unit. Some limiters were mechanical, a trip clip on the chain that contacted microswitches in the opener housing. Some were digital, you set limits with the turn of a screw.

Jot down the model number. With that, a PDF of the owner's manual is available from several sites, including Sears. It'll save you a bunch of time and hassle. It's usually on a small sticker somewhere near the controls or under the lamp cover.

Brad

[MechAg94]

Dumb question:  Did you clean cobwebs and such off the door?  I have had stuff come down and not trip the laser until it was pretty much closed.

[Hawkmoon]

Dumb question:  Did you clean cobwebs and such off the door?  I have had stuff come down and not trip the laser until it was pretty much closed.

Yes, I think I have already mentioned at least twice that I did that.

[Brad Johnson]

Yes, I think I have already mentioned at least twice that I did that.

I think I see what he's getting at... cleaning detritus off the door proper, not just from around the sensors. A dangly bit on the door could interrupt the beam without being obvious.

Brad

[Hawkmoon]

I think I see what he's getting at... cleaning detritus off the door proper, not just from around the sensors. A dangly bit on the door could interrupt the beam without being obvious.

Brad

Done.

But the problem is that the door closes fully, but won't stay closed. It closes -- and then immediately reverses and reopens. If it was a problem of something interrupting the light beam, it would reverse before closing.

[K Frame]

Does it have a pressure sensor in the bottom seal?

Some of them do, or did, at one time.

[Hawkmoon]

Does it have a pressure sensor in the bottom seal?

Some of them do, or did, at one time.

Nope. Too old for any of that high-tech gadgetry.