a.c brakets tighten a.c.

Hate to ask for help on first post, but i need it . My new EC 348 tri-power also has AC. It makes a noise like the belt is slipping.I havent spent a lot of time looking but i cant seem to find how or where to tighten up the A.C. compressor.I found in a catalog ,a idler pulley, for AC but mine...