Re: Keypad updating
Last March, I like you obtained a new to me AP900 and was asking similar questions. Frist step I did was to register my ownership of the mount using form on this link:
I then contacted AP using this link: Astro-Physics Contact Us (astro-physics.com)
The Folks at AP are very helpful and are amazing at providing support even for out of production product.
Hope this is helpful and enjoy your mount.