door will not unlock using key

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The keycam may have failed, example here, the latest design keycam can be easily identified as the colored changed to black. Replace either the keycam or chassis as needed to r...
 This could also happen if the tailpiece isn't installed in a KIL, FSIC, or SFIC cylinder.  The FSIC driver also could have come loose from the core in the spindle.
With the new FW package 2.19.0; AD300 FW 2.17.0 and AD400 FW 2.17.0 (released 09/23/2011) the firmware looks for a motor clutch switch change after a motor move command. If there is no motor clutch...
If the triangles in the spring cage spindle are not aligned properly the motor will not move enough to change the clutch switch. Is is very likely with a lock on the bench; but a properly install...
When the new firmware moves the motor three times without seeing the clutch switch change it reports to the SUS diagnostics that the motor is stalled. Aligning the triangles will let the motor move...
If the lock is mounted on the door, it is necessary to adjust the mortis/cylinder tightness and spring cage tailpiece alignments, making sure there is no binding or stopping of the spring...
Just align the triangles per the installation instructions to allow full motor movement.   - This will eliminate the SUS motor STALL report. - This will eliminate the three ...
Using the key from the pull side of the door does not retract the latch bolt on a rim or vertical rod chexit device.
CX98/9975 mortise devices will retract the latch bolt when the key is used on the pull side of the door.
This change was implemented in firmware package CO.A.6 (or later) to help the customer in the communication and coupling process between the CO200 (CO250) and the hand held device (HHD). ...
The green LED is to be lit up until the spindle (Triangles and Key Switch) are aligned properly; providing a visual indication of the problem.  
If the mechanical alignment of the triangles on the back of the outside escutcheon are not aligned, the CO200 or CO250 will not connect with the SUS/HHD and will appear to be unresponsive...
In firmware CO.A.6 (or later) the Schlage button on the CO200 (CO250) will turn green anytime that the spindle triangles on the front escutcheon are out of alignment or the mechanical key switch is...
When unlocking the CO200 door by mechanical key override, the green led will be continuously ON until the key is released. This will occur after firmware CO.A.6 (or later) has been installed int...
The Von Duprin 7500 mortise lock body ships in the NL mode.  Either the function of 7500 lock body has not been changed to the Classroom function or the NL Drive screw is not all the way down. Step...
  Tips for changing the function: The NL Drive screw will not be visible when lock body is set to Classroom function There is locktite on the screw that makes it seem like its turned down enou...