JAG was right about the piston being broken. That was the problem with mine. However, you'll find a small pinhole on the back panel inside the bag compartment. If you remove the bag and seal that little hole, it will fix your problem with showing a full bag. However, it will also not alert you when the bag is really full. If you still want directions on opening the canister, email me at stegenkj@hotmail.com.
stegenkj, December 2006