Can someone outline the method to center servo's and TX controls without resetting the computer for that model?

One of the guys at the club showed me how to do it with my Airtronics RD8000 last year.

What was happening was I was unable to get the proper throttle throw (did not know of a better way of putting it). I can't recall if I used an old model assignment and just reused the channel info for the new model (yeah, I crashed the old one and there was not much left to salvage.. picture a hard boiled egg after dropping it from five feet up.. that shell is what the inside of my fuselage looked like), let alone the right wing that was totally destroyed).

The servo only moved from the 90º to about 10º and back if viewing it from the rear. He had me do several things with end points and so on, but I cannot remember what that was. That represents the whole throw from the TX stick. So, the servo arm only moved about 80º rather than the expected ~ 170º.

If anyone knows that procedure, please let me know what that is.

Thanks.

DS.