How to converge projection TV?

I have a Sony 53 rear projection television which needs to be converged at the edges of the screen. The user menu only allows convergence at the center. Does anyone know the code to get into the service menu for convergence?
Dear Gsxer, Don't even think about doing that!!!. Did you know?, that your set takes about 3/4 hrs for the converegence to stabilize? I had an xbr53. Spend the $$$ and have the whole set up done.You get into that service menu;/truly a Pandora's box/nightmare.I had mine done by a pro. It took him 3 hrs to set the color temp/grey scale/convergence. BUT!!,what a difference,as in worth the price 3x over. The price was 350.You can't imagine he could make such an improvement;so much so that I got 2000 when I sold it to a friend.I have Pioneer Elite,same serv. guy.The improvement wasn't as great as the imp. to the xbr.BUT,I recomend/ don't play with it/and have it calibrated by a credentialled ISF guy.If you ever got into the serv. menu,in 4min you could do enough to get your set out of wack,that that would take 3hrs to undo/let alone the calibration itself.Spend the bucks,or live with it.
I agree with everything avguygeorge said. Don't mess with it yourself! I bought a Hitachi Ultravision 50" RPTV 3 years ago, it's been trouble-free. One of the deciding factors in that purchase was the picture (excellent!) and the fact that the set does it own autoconvergence itself. In the 3 years I've had it, I ran autoconvergence mode once when I got the set, and once again a few months ago. Enjoy your Sony, it's a GREAT set, but DO find a qualified ASF guy to set the convergence for you!