Before you send your stapler in, check to make sure that the power at the outlet is working. If you have another adapter of the same type, that you know is working, use it to check the stapler. If another adapter is not available, use a multi-meter to check the output of the adapter. It should match the output on the label (24VDC) - "Center Contact = +". If you find the adapter for the 520e or 690e faulty, you can order our part number 25003 as a replacement for $44.95.
Below are help files for various staplers which may help you with jammed staplers.