HELP! How do I access service menue on Zenith B27A11Z

I have a Zenith B27A11Z with a heavy green tint in the picture which can't be fixed by adjusting the color scale on the regular menu, and I've been told I can fix the problem through the tv's service menu but I don't have a remote and entering the service mode by "pressing and holding the menu button, then press and hold the volume down and channel down (or right adjust) so all 3 are depressed simultaneously" doesn't work...Does anyone know how I access this service menu?  Also, would this Zenith tube be interchangable with a 27" GE tube?