Originally Posted by triple D
If you look at the header end, is there a trigger switch there that the carrige bumps into when it reaches (closed)?
Thanks for all your help. Problem is solved. This GDO doesn't have any external switches. Everything is done INSIDE the GDO itself. I found the problem for why it hasn't worked the last few days, and I believe I found the original cause of why the nut went flying off the drive belt, thus flinging the belt that night.
1. The internal limit switches were not properly set. Triple D knew that. However, my inconsistant results of twisting the UP travel screw and the Down travel screw on the side of the GDO unit was a result of the screw unit being loose (came unsnapped from some plastic tabs) and thus the (worm gear?) wasn't interacting with the drive gear inside the GDO itself. In other words, when the owners manual says turn this clockwise or counterclockwise to increase/decrease the travel. 1 turn = 2", that assumes everything is nice and tight on the inside. So I got a clue when the two plastic screws (normally level just inside two holes in the GDO motor case) became all cockeyed and I had to play with them to get them to even turn. The other thing that went batty on me inside the GDO motor case was a pin came out (and is now missing) that holds a small plastic gear on the bottom of the main shaft (that turns when the motor turns) and then turns a smaller gear that adjusts a moving plastic shaft (that's in the middle of the up and down screws). YEP. This bad boy had no reference point. Since I didn't have a small nail or any bailing wire handy, I stuck some of those garbage bag twisty wires thru the hole in the shaft to hold the little gear on. works nice. I'll change this out soon.
2. What was I doing the last few days besides scratching my head on the humming motor and short travel? Well, we know the limit switches were not aligned properly in the motor housing of the GDO. I just knew if I was lucky enough to increase the up and down screws, then I'd get a little action. Mostly crashing into the header wall, or so it seemed. Tonight, I adjusted the UP screw all the way and it worked. It now traveled and hit the screw (that is in the rail to protect the GDO motor from getting run over by the Garage Door. So the rest of the night was mostly wasted until I figured out the stuff I already said.
3. Why do I think the nut came off in the first place and shot that belt all over the place (lucky I wasn't near it). I think the spring tension on the belt was not tight enough. I noticed after I found the nut on the floor and put the belt thu a hole in the "trolley-thing that moves the garage door when the belt moves", that I had to tighten the nut. But the owner's manual mentioned when installing the thing to jam a screwdriver between the spring and a washer, which will release the spring because the spring will push the washer over some small bolt looking thing. Bottom line: the spring wasn't released. Well, how can this be installed 9 years ago and no one 'released' the spring? page 3 or whatever of the manual. like step 2 of putting the thing togehter??? So, I didn't tighten the washer enough and tonight, the garage door really wobbled when you started it up either opening or closing. in mid-travel, it was ok smooth. I tightened the nut on the spring so the spring collapsed to be 1.25 inches long and that seemed to tension the belt pretty good. The next 10 or so open/close cycles were pretty smooth.
So tonight, I have it set so on opening, it stops about 3 inches from hitting the stop-limit bolt (no crashing - yeah!!) and when closing, it is smooth and stops right after the rubber thing under the door hits the floor. No reversing or crashing at all.
I'll likely play with the open/close force screws because I think i have them set to max and i know that's not good. plus i should test the safety/reversing thing.
Once again, thanks for your help and I think if anyone with a similar belt system/internal switch system, should really take the cover off the motor unit and see what's under the hood. Might save you a few hours.