[jshorva65]

You'll want to look in the Vertical Output circuit for the cause of the nonlinearity in most cases. The Vertical Linearity control will correct minor nonlinearity but it's a sign of circuit trouble if the control has to be turned too close to either extreme to get a good, linear sweep or if the control reaches the end of its rotation without fully correcting it. Electroytics are most often to blame and there are a few around the oscillator and output stages for decoupling and bypass. You've got full height, so I would say the waveforms' amplitudes should be close to correct unless the Vertical Size control has to be cranked way up. Good vertical locking indicates that the oscillator is able to synchronize correctly. Also check any waveshaping networks for an out-of-tolerance resistor or cap. If you haven't replaced all the paper caps in the vertical section, one of those could be part of the problem, but electrolytics are the most likely culprits. Vertical output amplifiers are basaically single-ended Class A audio amps designed to have very low distortion and optimum low-frequency response.