I decided to give digital ballast a shot. I bought four 400 watt Radeon ballasts. I built a new ballast box last weekend with the (4) 400 digitals and (2) 150 watt magnetics. When I fired them up, the 150 lamps turned on fine, however 400 ballasts cut on the lamps did not fire. I took one of the 400's out to bench test it. Again, the ballast cut on but the lamp did not fire. I tested a second ballast with the same results. I have also tested three new bulbs to make sure it wasn't that simple. Does anyone have any suggestions? Thanks in advance.