garage door travel adjustment

The sears garage door opener in this 7 year old house we just bought does not have any saftey mechanism to prevent closing on things. Recently one of our metal garage cans was in the way and I watched the door almost rip itself apart on closing.
Anyway, after dis/assembling and straightening all of the bent parts it looks good but it still has about 1" more to close, else it will let snow and rain in.
My question is, where do I look for the travel adjustment? There's a spring in line with the chain that I played with only to find that it's the chain tensioner. There's a pair of lapped metal arms or bars bolted together that have offset holes in them, but changing the offset would change the travel way over 1". Where do I look for the fine adjustment?
PS. I can easily get the door all the way down manually. There's nothing blocking.
--zeb
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Zeb Kagloonpop wrote:

but maybe they are the same? On the back of the motor light housing, I have two white knobs labeled 'Up force' and 'Down force'.
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The force controls have nothing to do with the amount of travel. You have to look on the unit's side panel for two plastic slotted screw heads. These control the amount of door travel. Here's an illustration: http://www.garage-door-hardware.com/LiftMaster-1245-limit-screws.html
Mind you, the Chamberlain Group is the company that makes the Sears and LiftMaster line of operators. So this LiftMaster illustration basically is the same as the Sears line.
Rich http://www.garage-door-hardware.com
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Thanks, Rich. Before, I saw the access holes for the travel control adjustments but there was nothing behind them. After reading your post, closer inspection revealed that the actual adjustment screws were on the other side of the box, where there are no access holes. Someone had turned the entire insides of the box 180 degrees. And it's not even a real 180 degrees, more like 160. The motor's mounted askew. However is works well and quiet. Is there a reason to all this madness?
--zeb
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