I have a craftsman 25 years old when I use either of the 3 openers remote,keylock.or door button the door comes down then goes back up.This happens 3 or 4 times before it closes and stays closed.

sensor in motor control needs sensitivity adjustment.
press the helpful button and chech link below

Force control Adjustments

Different frequencies.

The radio frequency has been changed so the two are not compatible.

Try this link
http://www.garagedooropeners.us/helpgifs/chamberlain_troubleshooting.html

Buy a new unit. this old unit is not safe and therefore parts will no be available.

If you can press and hold the wall button and the door will go down, you have a photo eye issue. Check the photo eyes at the bottom of the door.

try adding a little more down force

I read the GDO manual.
Thanks

Hello,Linda well this is your lucky day ,I have installed garage door openers for sears for 10 years and i can tell you that craftsman,chamberlain ,and liftmaster are all the same machine and manufactured under the liftmaster name , if you buy it from home depot it will be a chamberlain ,if you buy it at sears ,it will be a craftsman, and if you go to commercial building supplier it will be a liftmaster! now getting that out of the way even though they are all compatible ,there is one thing that stands in their way and that,s time ,For example if your chamberlain machine is 5 years old and you went to sears last week ,the chances of the frequency being the same are not good , most likely you have the wireless keypad , one way to test the sears keypad against the chamberlain machine is to locate the smart button on your machine ,this button allows for programming of remotes and keypads , to test and see exactly what im talking about take your remote and locate the smart button ,if you have three buttons on the remote press one of the buttons that are not being used on the remote ,above the smart button their will be a blinking light ,if you press your remote button you will notice the light go from a blink to a rapid flash , This is telling you that you are sending a signal for programming to the machine , well the keypad is exactly the same all you have to do is push the enter button on the keypad and have someone watch for the rapid blinking light ,if they are compatible the light will blink rapidly on the machine so all you have to do now is have someone press the smart button once on the machine your indicator light will now be a solid light you will have approx 60 seconds then to put a 4 digit code in the keypad and then press and hold down the enter button on the keypad , at this point you will notice the lightbulbs on the chamberlain machine to shut off and come back on this is to tell you that the machine accepted the code , after thats been done you can use your keypad , you can also find the owners manual to the chamberlain and follow the same instructions to programming the remote , they are identical in programing , if your keypad is not the same frequency you can also tell by looking at the frequency code on the backside of the keypad and also the chamberlain unit usually where the light bulb is will be its code

try adjusted the sensor controls on the sode of the unit other wise replace the logic board
http://www.chamberlain-garage-door-openers.com/circuitboardcompatibilitychart.htm