Garage Door opener Problems

I have a Sears screw drive opener, model #953992, 1/2 hp. I had this opener running for quite a while, and then had a bad water leak upstairs...water leaked into the garage ceiling and damaged the opener. I fixed all the water damage and went down and bought the exact same opener, thinking all I had to do was change the motor, and I wouldn't have to deal with assembling a new rail, door sensors etc.
I put the new motor on as planned and fired it up. All it did was hum briefly and stop, and then gave me 5 blinking lights in the back. I didn't pay any attention to where the trolley was on the rail when I installed it, but (after reading the directions) I learned that it was supposed to be positioned about 9" from the end of the rail, nearest the door. So I moved the trolley, but in the meantime, I turned the heck out of the adjustment screws trying to figure out what was wrong.
So now, the door runs okay, but runs the door all the way down, and right back up til the trolley hits the limit pin near the motor and stops. I try adjusting the limit screws, but it doesn't seem like it's doing anything. My fear is that I messed with them so much that they backed all the way out, or no longer work for some reason.
I'm thinking of calling a pro at this point, but if I could get it back to some kind of reference point to start out, I think I could get it adjusted...right now I have no idea where I'm at.
Any suggestions or should I call a pro?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I kind of doubt a pro would be that helpful in this case. Maybe go back to the store and if they have a floor sample, screw the adjustments in all the way, counting the number of turns. I assume they will stop at some point. If they don't then you might check the installation instructions to see if there is a help number to call. But I would be surprised if they don't stop at some point.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Disconnect the power cord, take the cover off and look at your limit switch assembly,
http://garagedoorsupply.com/limitswitch.jpg . You will probably find a plastic clip with a wire attached, contact, has come off the limit adjustment screw. Close your door and reposition the clip so that the metal contact touches the cemter limit contact. Reconnect the power and run the unit and make gradual adjustments until it stops where it is supposed to. Do the same for the up limit.
Rich http://www.garagedoorsupply.com

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Rich...Thank You for the great advice!
I took the cover off and found that the limit adjustment assembly is broken. Disappointing, but at least I know what's wrong with it and I'm no longer dinking around trying to adjust it.
Thanks again,
Mark
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You can use part number 41D3452 found at http://www.garagedoorsupply.com/chamberlain-liftmaster.html .
Rich http://www.garagedoorsupply.com
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.