61 inch Sony KP-61S35 convergence issues.

[MRX37]

I found a 61 inch Sony KP-61S35 rear projection TV. Upon getting it home and powering up, I saw that it powers up fine, gets a picture, but the convergence is off.

I managed to access the convergence menu and after adjusting it, I got good convergence in the middle of the screen. However, the corners of the screen still have poor convergence.

I am unfamiliar with rear projection TV's and I have no idea where to start looking.