Thanks to all who replied. Unfortunately I am still dumbfounded as to what is causing the cabinet to stop sliding out. I'm going to post a couple pictures, one with the cabinet in the travel position, the other with the slide out as far as it will come today!
It's in a cabinet by itself, a solid wall on each side as it's between the slide out bathroom door and the regular refrigerator, i.e. not domestic.
I've lubricated the slides also.
Bruce W
USAF (Ret.)