No power to front of controller or teach pendant

We have a Fanuc R-2000iA 165F Robot with a R-J3iB controller that won't fully power up. The controller won't get any power to the front of the controller, to the teach pendant, the fans aren't turning on and there are no lights on the servo amplifier. The only light that we are getting is the one light on the PSU below the F4 fuses(please see attached picture).

We have tried replacing the servo amp, the psu, made sure the robot had all 3 phases of power coming in. The next thing we plan on replacing is the transformer located in the back of the robot controller.

If this doesn't work, any other ideas on what this could be?

Yes, we made sure the on/off button was pressed. The majority of our controllers are the more modern controllers so I have definitely seen this exact scenario happen before.

As for replacing the parts we have a working spare controller right next to this one. So we are swapping parts out trying to diagnose the problem. We are not purchasing anything so although a little time consuming, there is no cost lost.