How to open an EXP No. 90042 stapler - Tools & Hardware - Others

It has a 7 year warranty. I would send it in anyway.

• Limited 7 year warranty & 100% Performance Guarantee

https://www.swingline.com/return-policy/

Looking at the image, I would guess that there are screws under the feet.

https://www.swingline.com/p/staplers/electric-staplers/optima-45-electric-stapler-value-pack-45-sheet-stapler-staples-staple-remover-s7048209b/

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http://smallbusiness.chron.com/load-bostitch-staplers-55757.html

How to Load Bostitch Staplers

normally the metal tray will just be able to slide out, or the top will be able to pop off.

Ungplug the stapler. In the area that you insert the paper, although its narrow, above where the paper is inserted you will see a metal straight/flat bar. Use a tool such as a letter opener and push the bar upwards. You should not have to push too hard. When you hear a click, you should be able to open the stapler. Remove the jammed staples. Plug in stapler and it should be work. (note: This is the how I fixed the Bostitch impulse stapler, but I was following instructions to fix another type of electric stapler and this worked)

Turn the stapler upside down and shake it to see if you can remove any of the staples. Attempt to open the top part of the stapler. If you can, remove the existing staples from the magazine. Then, unravel one end of a paperclip and attempt to remove the jammed staple from the head of the stapler.
https://smallbusiness.chron.com/open-stapler-jammed-shut-49396.html

Here's a video that shows how to open an older Swingline Tot stapler:
Vintage Swingline Tot Stapler Demonstrated

There's a rectangular opening at the front end of the stapler. You can insert a rod that fits in the opening, and push the staples back out if they're not hopelessly jammed in-place.

"The staples load from the rear of the stapler. At the back end of the is a piece of black plastic that extends beyond the end of the stapler. This device holds the staples inside the stapler. To open the area where the staples are placed, push this extended button and lift up on it. The spring device that holds the staples inside the stapler will then slide out. Place a new strip of staples inside the stapler on top of the two metal guide rails. Then insert the spring device to lock the staples in place. The stapler is now loaded and ready to work. " hope this helps you out

Located on the end opposite of where the staples come out, there is a spring loaded cap. Push it in toward the base of the stapler and slightly down to release the retaining hook. then let the spring release the pressure rod and pull it out. Connedted to the end of the rod you will see a plunger that is shaped like a short run of staples. Make a mental note of how and where this plunger slides into the base of the stapler. Place a run of staples into the stapler in the same manner that the plunger fits then replace the plunger into the same place following the run of staples. Compress the spring into the stapler and attach the hook as it was. Now you are ready to work.

NOTE: If you cannot compress the spring enough into the stapler you have inserted too many staples, just remove some of the run of staples and try again.

Push the black half-oval button at the hinge to release the staple cartridge. Extend the staple cartridge from front of the stapler, add staples, push back in.