I hear there might be a couple different CRTs this unit could be using. I have not opened it up to take a look for a HP part number but If anyone has a good working CRT for it I would be interested inn acquiring it. It has to have good brightness, The one I have you can barely see the display turned up full. I use a scope now on X,Y,Z to see the display but it is still not the same as a good working one.