Sears Garage Door Opener Problem?

Question

I have a Sears Garage Door Opener that was purchased in about 1993. It is a Craftsman Model 139.53625SR (1/2 HP). The door itself is not in a bind or sticking, but the opener reverses near the end of its travel on the way down on an irregular basis, usually when it’s humid. I have adjusted the down Force s***w to the extreme limit to allow the door to close. Does this mean the primary circuit board is bad? Given the cost and the opener’s age, am I better off buying another opener? Again the door is easy to open / close by hand, with no evidence of sticking. There is no light detection device at the base of this door.

Answer 1

lube the rail were the trolley travels sears / operators come with a three piece rail, check the nuts to see if tight, 7/16"

socket. and as stated ,above the chain could be hanging up on one of the bolts or rail section.

Answer 2

it sound to me it hanging up on the chain. and you have to get up three and watch it open to the point whereit hang up. then you can fix it . put some power oil on the chain to up to. then if you can,t get it then go out and buy a new one , put i would not put a lot of money in to it.

Answer 3

If it was me, I would replace it because of the age but you could try doing some troubleshooting with the unit.  Try oiling the chain and see if that works, also, you could check the lenses on your sensors and make sure they aren't obstructed or dirty

Answer 4

It could be crud building up on the internal circuit board, remember it is in the vicinity of the motor and gears so could get dirty.  When moist, it gets more conductive, enough to throw off the electronics and cause issues like this.

Solution, take the board out of there and clean it; I hesitate to tell you how aggressive to get with the cleaning depending on how dirty it is, but something like a paint brush is a good place to start.

Also, there is (probably) a little plastic disc or thingy on the end of the motor shaft inside the unit and a small sensor board - this detects the speed of the motor and if it slows down indicates that the door is jamming so will stop it.

Check that affair out to see if everything is lined up and tight.  Believe it or not, on mine the photosensor on the small board itself had come loose and needed resoldering, how that happened by itself who knows?  But you can closely inspect any solder joints and connections for integrity while you are in there.