I have a 1/2 hrspwr opener that has been working fine for years. Now when closing, once it gets all the way closed, it immediately goes back up. The "traveller" appears to go too far now, because it continues even after the door is all the way down, until it hits the "stop bolt". I've tried the down "limit adjustment screw" but it doesn't work at all. It is all the way in, compared to the "up" limit screw right next to it.

Any way, the only way I can see to shorten how far the traveller goes is to shorten the chain with a "chain break".

Any experience with the adjustment screw not working?

Thanks............