[compucat]

The height control is concentric with the brightness control. I have the 25MC33 chassis, yours should be similar. The brightness knob should have a small hole in the center (if it's on the correct shaft). Insert a thin flat blade screwdriver and adjust. The linearity control is in an unmarked hole in the control panel as posted earlier. They are a little tricky to locate but the Zenith engineers were thoughtful enough to put these controls in front where the settings can be observed much more easily. You can touch up the vertical as needed without ever moving the set. I hope this helps and enjoy that roundie. There is nothing like a Zenith.