Open the motor cover.  There is usually two pegs/pins/blocks of differing colours (red/green for example).  Depending on manufacturer, you may need to move these guides to a marked point after the motor has stopped, or just move the guide slightly each time until it works as required.

Often there is a tech number on the door or motor, maybe worth asking for advice.

I think my door mechanism might be of a different type; I believe the motor itself is part of the cylinder that the door winds around.

Here are some pictures:

(rather out of focus, sorry!)




(not sure how to rotate this ...)

I did try turning the power off & on again with the door in the closed position, but that didn't make any difference.  The circuit board in the control box has two small push buttons; I tried pressing each in turn hoping that it was a reset, but to no apparent effect -- without instructions, I don't know whether you need to press the button for longer, press both together or something more complex still.  There isn't any specific manufacturer name on/in the control box.  I did try googling with the little information I could spot, and didn't come up with anything very detailed.

I'll have another look tomorrow ...

Thanks ... I'll try that.

Get reading

I guessed PDT was the manufacturer, and googled PDT limit switch or limit setting.

http://www.snr-garage-doors.co.uk/pdfs/seceuroglide_installation.pdf

You could push the cables in a bit as well so they catch on the cable-grip.