Brendon is right , you have to wind the thread back out , left side of the photo , and that will release the pressure in the spring , right side .
Be sure all the parts line up properly before you wind the thread ( left side ) right up tight again , you have to re\wind the thread back out again , reset the DEC and you will have the movement again , about 15 degrees at a setting , plenty for visual work if even roughly polar aligned .
You will be ok once you suss out how it works .
Brian.