How to Repair a 933 Printhead Error T640

By Ty Arthur

Your Lexmark T640 printer has a variety of internal hardware components and associated software that may stop working properly over time. If you are receiving an error message on your screen named "Printhead Error 933," you are probably experiencing problems printing or all the prints are faded. The 933 Printhead error is usually caused by a loose cable inside the printer. Fixing the problem requires opening up the printer and manually fixing the cable.

Things You'll Need

  • Phillips screwdriver

Step 1

Press and hold the power button on the front of the Lexmark printer until the device turns off. Wait one full minute, and tap the power button again. Open a text document, and try printing again to see if the issue is resolved.

Step 2

If the problem continues, turn off the printer, and unplug its power cable. Push the release latch at the front of the printer, and pull down the lower plastic door. Press the release latch inside the top plastic door, and lift the door upward.

Step 3

Push the two latches at the far left end of the printer. Pull the plastic door at the left end of the printer toward the left. Use a Phillips screwdriver to loosen six screws holding the metal shield to the left end of the printer, but do not completely remove them.

Step 4

Move the metal shield over to the right to reveal the multi-colored cable at the top of the system board. Unplug the cable and plug it back in. Check to ensure the cable is properly seated and is making a full connection.

Step 5

Slide the metal shield back into its original position, and tighten the screws you loosened earlier. Push the three plastic doors back into place, and plug in the printer's power cable. Tap the power button, and start a new print job.

Tips & Warnings

  • If you continue to experience printing problems, you may need to install the latest driver software. Navigate to the support website for the Lexmark T640, and click the "Downloads" link. Click the driver download for your computer's operating system. Double-click the file, and follow the on-screen instructions.