Ok, I'm a custom installer for a retail chain in the midwest. I had an MX-700 that was stuck cycling through the Test Mode, the test that comes up when you first put batteries into it. So I did what any responsible remotecentral citizen would do and looked up a couple posts regarding the issue. Came up with these two threads:
[Link: remotecentral.com]
[Link: remotecentral.com]
To save you from reading the previous threads, basically there's no answer. Anyway, I took the liberty of calling URC, and he let me in on the secret.
While the test mode is working, press and hold the Main and Stop buttons at the same time for approximately ~7 seconds. The man will stop running and everything will basically appear to freeze up. At this point you can download any configuration to the remote that you'd like and you should be good to go.
I would assume that this will work for any of the MX remotes, perhaps for the MX-500 you could hold Main and Stop down, then simply Main and Enter to get into the programming mode and go from there? If I had other remotes that did this I would test it, but alas it seems to be a somewhat rare issue. Anyway, I hope this information helps someone, if not today, maybe others will read it and store it away for future help for all.
Mike