Toshiba 27" CRT TV (27A33, 2003) bowed in at sides

[CRTguy]

My set has a pincushion issue where it bows in at each side, horizontally. There is no option in the service menu to fix this. I've owned three of this model and they've all had this issue. What could be causing this? Could it be as simple as some faulty capacitors in the vertical deflection circuit? The picture is excellent otherwise and my TV only has 6,000 hours on it according to the service menu.