Since you have problems with opening, are you absolutely sure a door spring hasn't broken or the set screws (if it's that sort) haven't slipped (rare)? Before you can begin to troubleshoot the opener you must be sure the door is balanced without the opener hooked in. Only then should you play with opening and closing force and safety devices. If you try opening the door by constantly mashing the wall button too much you could fry a board, also rare.