In Level mode, you'll need to contact us for the alignment procedure. In GR (gain reduction) mode, take off the top of the unit and warm up completely. BE VERY CAREFUL AND TOUCH NOTHING ON THE INSIDE OF THE UNIT; POTENTIALLY LETHAL VOLTAGES INSIDE. EVEN WITHOUT POWER CONNECTED CAPACITORS WILL STORE A CHARGE THAT CAN SHOCK AND POTENTIALLY KILL. If you are unfamiliar with doing this, please have a qualified service technician do this for you. Set the meter select switch to GR. With a small, flathead screwdriver, adjust VR4 near the middle, left side of the main board until the meter rests at 0. VR4 is located in the middle of a line of 3 trim pots next to a large, black square (U5) and to the back right of the vacuum tubes. It is helpful to switch back and forth from Level to GR to make sure the meter sits in the proper position.