Audio research ref 5 reset tube hours

How do you reset the hours?
Thanks mike
Mike, if you open the top cover you should see a small red square button on the back side of the face plate. Just press it and that is all. Or at least that is how it is done on an LS26 and I am sure it would be the same. Also you Manual should explain this procedure as well.
Same with the AR Ref3 there is a reset button on the backside of the face plate.