Question
My Hardie HR-6100 is probably over 10 years old.

When our sprinklers did not come on, I looked at the controller panel and noticed that the time display was off though it was in Run mode.  I shifted into Manual and then back to Run but still nothing.  The fuse was intact and I assumed that the transformer had failed.  However, a new replacement transformer did not light the display and the unit still seemed dead.  Though the fuse looked intact, I also replaced it without any benefit.

Does this mean I must replace the controller timer and, if so, can I use an Orbit 27956 to do so by connecting the wires from the 6 stations and the common wire and of course the transformer wires?

Thanks very much.

Answer
Hey Eli, yeah that controller has not been made for about 15 years, and needs to be replaced. Almost any controller will work, just mark the wires as you take them off #1, #2 etc. and especially make sure you hook up the common wire correctly.  The new controller will have its own transformer and you will not use the existing transformer. I am not familiar with the orbit 27956 controller because it would not be considered what a professional would use. I would suggest putting in a Irri-trol "Rain dial" controller. This controller is the next generation of your current HR-6100. Like the 6100 it is also available in an indoor model.
It might cost more then an orbit controller, but it will last a lot longer and will be cheaper in the long run. Good luck and have a great day.