The transfer unit on a Xerox Phaser 7400 colour LED printer presses the paper to the drum so the image can be placed on the paper. After unit replacement, the printer should automatically reset the counter. If the counter does not reset, you may have installed the transfer unit incorrectly, or the unit itself may be defective. To reset the counter manually, you will need to reinstall the unit, and if necessary, enter service diagnostics.
Lift the top cover by using the handle above the control panel on the front of the printer. Lift out all four imaging units and place them on a piece of paper. Use another piece of paper to cover the imaging units to avoid light exposure. Raise the two gold-coloured latches at the front and back of the transfer unit, then use the two handles to lift the transfer unit out of the machine.
Reinsert the transfer unit by placing the left end into the bracket first, then the right. Press down on both latches to make sure the unit is locked into place. Reinsert the imaging units and close the top cover. If the message is gone, the reset is complete. If not, you must enter service diagnostics and manually clear the count.
Turn the printer off. Turn it back on while holding the "Back" and "Help" buttons at the same time until the words "Entering Service Diagnostics" appears. This occurs shortly after the Xerox logo centres on the control panel. If you get past the logo and don't see the message, turn the printer off and try again.
Press the down arrow on the control panel until you get to the option for NVRAM Access. Click the "OK" button on the control panel. Scroll down with the down arrow until you see CRU Counter Resets. Click the "OK" button to select. Use the down arrow on the control panel until you reach Reset Transfer Belt Count and then click the "OK" button. Press the "Help" button to toggle the option of Yes or No to reset the transfer belt count. Click the "OK" button once you have it on Yes. Turn the printer off and back on.
Always replace the consumable item that causes an error before entering diagnostics. If an error occurs immediately after replacement, it often means the consumable is defective. This is also relevant if the consumable replacement message doesn't clear after the consumable is replaced.
Don't mess around in diagnostics. Do what you need to do and get out. It is possible to turn your printer into a very heavy paperweight if you adjust settings without proper instruction.