My older Craftsman garage door opener comes down about 6" & then goes back up. I just replaced all the rollers o& the opener worked fine. Then I tightened the chain on the opener & it worked ok once or twice, but that was it. Could the chain be too tight? Sensors look ok.

If the main light flashes 10 times when the door goes back up it is a door sensor problem. You chain should sag just a little. If you tighten it too much it will click as it goes over the sprocket. You can increase the down force which is an adjustment near where all those white wires go. A 1/4 turn should be enough. Release the door from the opener and operate it by hand. It should move freely and when you have the door approximately waist high it should stay put. Neither raising nor closing.

I have a Craftsman 1/2 hp GDO, Door goes down fine, but when I go to open it, it only goes up about a foot and sometimes go back down or just stay where it stopped. Solve this problem please?