To my knowledge, there is no backdoor password for the X series.
You need to call the factory help line (in the US it is 800 423-9883, not sure about Canada) and provide them with the internal serial number of the recorder, a 6 or 7 digit number starting with 8: 8xxxxxxx
The internal serial number is on the paper tag above the CE logo mark. It's also listed on one of the status pages
menu > status > system > general > serial number
Using the internal serial # and the date, they can generate a temporary password for one day's use, assuming the recorder's clock is the same date as the day you call in. It's worth checking what date the recorder thinks it is, in case someone missed daylight savings time change last time around. I assume that they can adjust the password for whatever date they're given.
I can't recall whether you get a user name or not to use with the temporary password.
Once you log in, regular configuration menu items are not available, only edit > passwords, if I recall properly.
IMPORTANT: Do not "reset passwords"
"Reset passwords" wipes out all user names, passwords and policies and you have to start over with any or all security (password) settings.
Temporary access allows you to either reset an individual user account or to add a new admin user.
My notes indicate that I had a problem trying to "reset" an administrator account and that I ended up creating a 2nd and 3rd user accounts with administrative access.
Dan