I was called out to a site today that had all of their phones go dark on them.

The first thing I saw was the controller's 3-front panel LEDs were flashing orange. I did a quick power cycle and when it came back up the CPU LED was a steady green with the system SD and optional SD off, after a couple of seconds all three would blink orange for a second and them back to the CPU LED showing green and the other two off. This continued with no end.

I haven't been able to find anything that comes close to explaining what the LEDs flashing like that mean.

Does anybody have any ideas?

They are sending out a new controller to replace this one, but I was wondering if something else is causing this

Assuming its your customer and you have it backed up, them i would reset the unit and up load to backup.

What did System Status say? Possibly that the unit was running on backup firmware, which would mean that the SD card got corrupt..
Since a new box is coming, i would also use MANAGER and rebuild the SD card, to be safe.

Here's your guide to the LEDs and their meanings:
http://www.touchtonetommy.com/Files/Checking%20the%20LEDs.pdf

They are not my customer so no back-ups and they just told me that they have a team that will install the new controller tomorrow

Thanks for the reply, but I was just told that they are sending a different team out tomorrow to do the change out.

I found that LED guide, but it doesn't cover the LED sequence that I was seeing.

It turns out the people who had me go out are going to send a different team to do the change out tomorrow.