Hi pookie, sad to say, but it's probably the end of the road for the monitor. The focus is determined by the various voltages on the tube electrodes. When the tube ages, the cathode emissions and the phosphor efficiency deteriorate, and the only way to compensate is by increasing the contrast and brightness settings. Unfortunately the generators of the electrode voltages can't maintain the currents required and the tube defocuses. You can usually prove this by seeing the picture go out of focus as the brightness control is turned up.