The Spectra IV 29X and 36X will sometimes lose the ability to focus when zoomed in all the way or zoomed out all the way.
Pelco Cameras, Pelco Video Management
This appears to be an issue with firmware and a race condition that the focus motor and the lens motor get out of synch with one another. It is an intermittent issue that happens once in a while.
If you reset the camera in the camera menu this will clear this and resolve this issue.
steps to clear;
1. Use "preset 95" to get into camera menu
2. At bottom of the menu put cursor at "reset camera"
3. Press Iris open to do function.