Comes with its own backplate which is smaller than that of the 9930 keypad
And yes disconnect old keypad and reconnect the same labelled terminals on the new keypad
If it’s still saying checking system it sounds like it’s not returned from engineer mode. So no tamper should go off. But once the power is dropped from the panel that would stop the noise anyway
Loosen two screws underneath the panel
Pull the panel away from the back box
Remove the screw in the centre of the panel holding the battery compartment lid in place
Unplug the battery
Unplug the AC lead to the left of the compartment (red lead white connector)
system is powered down...
Remove the battery then remove the mains supply to the alarm it should have a fused spur nearby. Simply pop the fuse out that to remove mains power to the system