So, i was attempting to setup a shimano 105 (5600)front/left shifter. At some point as I was messing with it, it stopped working. It still pulls the cable through when you operate it, but it doesnt click now. From the small cog, i can push the lever and shift it up to the big one, but as soon as I let go, the derailer drops back down to the smaller one. I disconnected the cable from the derailer and worked the shifter and it doesnt click at all. Its like the ratcheting mechanism inside the shifter broke. Is this repairable in any way, or is a replacement the only way?