Distorted Screen on RCA P52731WK?

I just had my TV repaired at a local TV shop, and they replaced the High Voltage Distributor. Got it home, and it has a good picture, but when you look at things like the TV Channel guide, the lines are not straight. It seems that the left and right edges are taller (vertically) than it is in the center. It's not too much to distort a full screen movie, but it is noticible when you pull up the channel guide or watching a letterbox movie. The colors stay good at the distorted area.

This was not happening prior to the previous repair so I went back to the local repair shop, and he told me that this could not be fixed.

I am here because I do not believe this to be the case. This set has a LOT of adjustments that can be made behind the front grille, as well as inside on the RGB guns.

I have quickly searched the net for a service manual, but could not find one. I am no stranger to fixing electronic equipment, but have never done a TV, but can make adjustments IF I knew what to adjust.

So - 1/ Any suggestions on the best place to find a service manual? 2/ Is my local TV repair shop just being lazy and not wanting to fix it under warranty?

Thank you in advance...