I have a RCA D52W20 tv (didn't buy it, came free with furniture) and I notice quite abit of overscan when watching HD. For reference, the right edge of the small circle in the CBS logo touches the right side of my screen.
I've tried fixing it by entering the tech setup and playing with the different positions. Problem I'm having is the center of the picture "bows" once I get the picture centered.
I guess I'm just getting impatient and I'm wondering if it's really worth it. My thinking is if the picture is zoomed in abit (~2" all around) would this not cause some resolution problems?
If there is no "H-size" or "V-size" or similar in the service menu, there may be nothing to do.
I found some potentiometers on my chassis (Hitachi) that allowed me to reduce the overscan some, but required many hours in the DCAM convergence to straighten things out afterwards due to the "bowing" you mentioned. This route is not recommended since it can apparently damage your TV by taking things "out of range".
Also, see the following post on the service menu and heed the warnings:
I have an RCA Scenium 61, and the menu will be the same as yours. You can fix the overscan with the service menu. You will be able to adjust the "bowing" with one of the adjustments. Once you are in the service menu, write down all the numbers, then start adjusting, slowly, so you can figure out what each thing does. I can't remember the name of the adjustment you need, but it is there.