One thing you can check if it hasn't been mentioned is the horizontal sweep rate. Make sure the cal knob is locked and set the horizontal to 1us/div and apply a 1MHz signal (or whatever combination works for you that would give 1 cycle per division). Then check and see if your cycles are squeezed to less than a division, in which case the sweep is compressed, or if the cycles are approximately 1 per division, in which case it is truncated. If compressed you probably have a horizontal gain issue, if it is truncated, a sweep generator issue. If it is 9 divisions long, it is possible that some clown has gone in there before you and diddled the adjustments to hell--so you might start with the calibration and adjustment part of the manual.