From what I can gather, it appears someone named "Pee Wee" who had a lot of knowledge about Philips/Magnavox televisions, used to post on here several years ago - no longer does.

As far as your problem, from what you're describing, it is not a horizontal deflection problem, but a Vertical Deflection problem - that's why there are only horizontal scan lines in the center of the screen.

While it could be a semiconductor failure, I would first suspect that an electrolytic capacitor(s) failed in the vertical deflection circuit - simply due to old age and drying out.

Unless you have electronics troubleshooting experience, bin boxes of misc parts sitting around, and just simply are looking for something to do, it is just simply beyond economical repair.