"Pincushion" problem on Philips TV

[larschr]

I got this Philips TV from a school before christmas, and it works great, except for one little thing: There is some kind of picushion adjustment fail on it. Look at the screenshot, on the right side on the picture. Sometimes it is also visible on the left side. It is most noticeable when i use a high quality signal source, like a Playstation or a DVD player. It also depends a lot on the colors and brightness/contrast levels in the picture. I can not find any pincushion adjustment inside the TV, only H size, V size, H position, V position and so on. I suspect that the TV may have been droppen on the floor or something, and maybe the electron gun is knocked out of position. Or could there be something else? I do not think the TV is much used. It has a great sound system: 20 watts output power, bass reflex speaker system, separate bass and treble controls and audio line out. Maybe it´s not vintage yet (it´s from 1984), but it soon will be. By the way, does anyone know the model number? The label is missing.