Still encountering error 50.4 on my hp 400 printer after changing the fuser and power source outlet

1. First thing you have to do is to cancel all the pending printing jobs in the queue.
2. Now switch-off your printer and leave it for few seconds to cool it down.
3. After cooling down the printer completely, the fuser failure error appears on the display screen.

1. Turn the printer off and unplug it for 30 minutes; then turn the power back on.
2. Try a different power cord. DO NOT use extension cords to plug the printer in.
3. Remove the surge protector or UPS/CVT device and connect the printer directly to a power source.
4. Try a different electrical circuit. There could be an issue with the line voltage going into the printer from the power source.
5. Turn the printer off and unplug it. Let it sit for 30 minutes to let the fuser cool off. Carefully remove the fuser; IT MAY STILL BE HOT USE CAUTION. Examine the fuser, if any damage is apparent the fuser may need to be replaced. If no damage is noted reinstall the fuser, plug the printer back in and power it up.

50.x Fuser Error

1. Remove the printer from any UPS supplies, additional power supplies, or power strips.
2. Plug the printer into a wall outlet to check whether this resolves the problem.
3. If the printer is already plugged in, try another power source in the building independent of the one being used.
4. The line voltage and current source at the printer location might need to be inspected to make sure that it meets the printer's electrical specifications.
5. Turn the printer off then on.WARNING: Be careful when removing or reseating the fuser. Temperatures can reach 400+ degrees Fahrenheit.
6. If the message persists, turn the printer off for 30 minutes to allow it to cool, then reseat the fuser after checking the internal wiring connections on the right and left side, ensuring that these connections are properly seated.
7. If the 50.1 or 50.2 error recurs after power-cycling the printer or when trying to print, try installing a known good fuser from another HP LaserJet 4100 series printer, if available.
8. If the fuser is near or at the end of its estimated life expectancy (approximately 200,000 pages), then replace the fuser. After replacing the fuser, print a Configuration page, a Menu map (shows fuser settings), an Event log, a Supplies status page, and a Usage page, to reference the status of the new fuser and to ensure that the previous fuser settings are in place with the replacement fuser. To print an Information page on the HP LaserJet 4100, perform the following steps
   1. Press the MENU rocker key until INFORMATION MENU appears on the printer display.
   2. Press the ITEM rocker key until PRINT CONFIGURATION (or until PRINT MENU MAP, etc, appears in the printer display.
   3. Press the SELECT button to print the selected information page.
   To print an information page on the HP LaserJet 4100MFP, perform the following steps
   1. Press the MENU button.
   2. Press the DOWN Navigation button until INFORMATION is highlighted.
   3. Press the RIGHT Navigation button.
   4. Press the DOWN Navigation button to highlight PRINT CONFIGURATION (or PRINT MENU MAP, etc, appears in the printer display.
   5. Press the SELECT button, the button with the checkmark on it to print the selected Information page.
9. If 50.x errors persist after properly installing a known good fuser, or if the errors follow the questionable fuser (provided it is not near the end of its estimated life expectancy), contact HP for further assistance.

1. Turn the printer off.
2. Verify the fuser is properly installed and fully seated.
3. Turn on the printer.
4. If the message persists, contact HP Support.