ok, this wont be the best ever description and images, but it will get you on your way im sure.
image1 - the 1200 ryobi plunge router.
image 2 - Remove the four Screws that hold down the top cover and pry the top cover off.
imjage 3 - Remove the four Plastic "thingies" with a flat screwdriver.Under neath them are four screws which you need to loosen and Cut the Brown Wire "Yes Cut it"
image 4 - here you can see one of the screws that was hidden by the plastic "thingies"
image 5 - you can now lift up the entire casing and remove the springs.
If memory servers when you cut the Brown wire, you also eed to disconnect all wiring as well - push lugs, so you can life the cover enough to get the springs out.
Hope this helps.
any questions send me a pm.