You require a 2 & half mil allen key to open the panel.
There is no default master code in the 5000.
The installer code “000000” cannot be changed.
If you powered up with your finger on the “Program” button & jumped out of program mode, this would default the panel.
From Installer programming (program light flashing) you can only have access to installer programming options, you cannot access client (User) programming options.
Back dooring by powering up on the End button & all other programming can be done from any other 5000 series remote keypad.
The 5000 series local panel gives you 4 codes including the master. But if you have a dialler connected you gain additional codes from 5 to 15 that need to be addressed with a zero in front. E.g.: User 5 – Program 05 End code end, code end, User 10 – Program 010 End Code End Code End etc.