Hi moetyler,
To try to resolve the B204 error, please follow the following steps:
1. Turn your PIXMA MG6821 off and disconnect the power cord and USB cable (if connected).
2. Stand your PIXMA MG6821 with the right side facing down.
3. Push the open lever to open the transport unit. When you open the transport unit, support the machine with your hand so that it does not fall down.
4. If you see jammed paper or any foreign objects, pull it out slowly.
5. Close the transport unit. After you close the transport unit, take back the machine in original position at once.
6. Plug your PIXMA MG6821 back in and turn the machine back on.
7. Confirm that your PIXMA MG6821 is powered on and press the Open button. (The paper output tray will open.)
8. Lift the scanning unit (printer cover) completely. The print head will move to the center. Note: When the scanning unit (printer cover) is opened more than ten minutes, the print head moves to the right side. If this occurs, close the scanning unit (printer cover), and open it again.
9. Open the inner cover.
10. Press on the tab at the end of the ink tank to release the ink tank, then remove it from its slot.
11. Lift the printhead lock lever up and then back down.
12. Re-insert the ink tanks into the print head. Note: Press the mark "PUSH" on the ink tank firmly until you hear a click.
13. Ensure that all the ink tanks are installed properly and the ink tank lamps light red.
Attempt to print.
If the above procedure does not resolve the B204 error, your PIXMA MG6821 would require service. You are eligible for Canon's Upgrade Program. This is for out of warranty units which have been diagnosed to require service, or for some reason are incompatible with a new or upgraded system. This option allows you a one-time opportunity to purchase a replacement product, discounted from the list price.
To help you get up and running quickly, we also offer free standard shipping (if the order is completed by 12:30PM ET). If you would like to take part in this option, please call our Sales Department at (866) 443-8002 seven days a week, 8am to Midnight. Let them know you have been working with technical support and the Canon Upgrade Program was offered.
