Wont operate correctly

It's quite possibly under the cap it's the head valve. Does it shoot at all ?
If so hold the trigger after the shot listen for where air is leaking.

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)

Craftsman Electric Stapler Model #193.684231 aka 9-68423. (Came out in 1984)

Can take up to 5 different size staples depending on your project. One feature is the "dual power" knob at the top which allows you to use "HI" or "Low" impact depending on the size staple used. Sorry about the blurry pictures, they are sharp on my computer. Try Googling the model number or looking on EBay. "No. 6" means "Heavy Duty Wide Crown .417 size."

The head valve is sticking. You can remove the screws that hold the head valve on, remove the head, remove the valve (take pictures first if you have to. Make sure you understand how it fits together) and lightly grease the o-rings. I use white lithium here at the shop when I rebuild nailers and staplers. Once reassembled it may work correctly.

Stanley Bostitch has been sold to Dewalt. The link below has all the information and parts for your gun. Good luck with your projects.

http://servicenet.dewalt.com/

1. Make sure you have the correct staples for the machine, Swingline Hvy-Duty Staples for 90010 Stapler, 0.625-Inch Leg Length, 2500 per Box (90009)

2. Check the staples to make sure there are no visible jams. Remove some staples from the row if this helps them fit.

3. If you continue to have problems, contact the manufacturer at http://www.acco.com/swingline/, or
Repair Service/Technical Support:
Phone: 800.790.7787

They will replace the stapler if needed.

obvious answers are 1. a burr on the striker, 2. a bent striker. 3. a trapped staple 4. a broken return spring. other than that I cant help you without seeing it.

Check to see if there is any foreign object jamming the striker bar. These units also have a diaphragm that sometimes needs to be replaced. If you do not have an automatic oiler on the line the diaphragm could have cracked allowing air to pass through. The Stapler can not build up the necessary pressure to fire the striker driving in the stapler. Damaged or cracked this will need to be replaced. Not difficult and easy to DIY job. Do NOT hook up to air when doing this service. Dirt and grim can also jam the unit. Clean lightly oil, work the unit and see if it frees up. I typically put a few drops of oil made for pneumatic tools directly into the unit. Each time I pull the pneumatic tools out to use. I do not have an inline oiler. :)
Typically at the Male nipple connection where the brass female connector hooks too. 2-3 drops only!
Hope this helps!

before going about rebuild get can of carburetor spray cleaner and stray the ram area lots of times the glue that holds the staples/or nails builds up and stops up the ram rod spray the rod a few times than with air hooked up dry fire if it frees up lube rod area

Did you look for a staple jammed in the driver mechanism? If the piston is stuck down, it won't respond to the trigger. Try smacking the top of the stapler onto a wooden bench to see if the force will release the piston. Make sure that you use air-tool oil for lubrication inside the tool. Hope this gets you running!