Updated: Nov 15, 2019
Technical Service Bulletins
LaserJet 4200/4300/4250/4350/4345 Fuser
Hewlett Packard has identified a manufacturing flaw in some LaserJet
4200-4250-4300-4350-4345 printers which may cause a gear inside the rear
of the printer to fail prematurely, resulting in grinding noises, wrinkled pages
and/or paper jams.
If your printer exhibits any of these symptoms before or
after replacing the fuser assembly, try the following field adjustment:
Refer to the service manual where necessary.
1. Remove the Face-up Exit Tray.
2. Remove the Fuser Assembly.
3. If the Duplex Unit is installed, remove it from the printer. If it is not installed, slide
the Duplex Cover out from the rear of the printer.
4. Remove the Left Side Cover.
5. Remove the Formatter Cover.
6. Remove the Formatter Assembly.
7 Locate the seven M3 screws securing the Power Supply - there are four behind the
Formatter Assembly and three on the other side of the printer. Loosen all seven
screws but do not remove them.
8. While facing the rear of the printer, grab the Power Supply and pull it towards you
and downward. This will situate the screws in their lower-inside position.
9. Continue to hold the Power Supply in this position and retighten all six screws.
10. Replace the Formatter Assembly, Formatter Cover, Left Side Cover, Fuser Assembly
and Face-up Exit Tray.
11. Test the printer for at least fifty pages to ensure that the issue has been corrected.
12. If the printer continues to exhibit the original symptoms, the Swing Plate Assembly
(RM1-0043) is worn and must be replaced.
!!! ENSURE PRINTER POWER IS OFF BEFORE REMOVING OR INSTALLING FUSER !!!
Paper Jam Solutions For Laserjet Printers
Printer Service And Parts Glossary
When replacing the fuser, it is highly recommended that the swing
plate assembly is very carefully inspected. If the swing plate gear that drives
the fuser is even slightly worn, we recommend it be replaced immediately. If
not, this can lead to premature failure of the newly installed fuser.
The various 4200 and 4300 series fusers look almost identical but are not
interchangeable. They can easily be misidentified, leading to problems upon
installation/replacement. The chart below shows the error code displayed in
each instance of the wrong fuser being installed any into of these printers.
In 4200 RM1-0013
50.5 FUSER ERROR Printer at power-up
50.5 FUSER ERROR at power-up
In 4250 Printer RM1-1082
13.20.00 JAM IN TOP COVER AREA at power-up
50.5 FUSER ERROR at power-up
In 4300 Printer RM1-0101
50.5 FUSER ERROR
13.20.00 at power-up
JAM IN TOP COVER AREA at power-up
Important Note: A 50.5 FUSER ERROR indicates the incorrect fuser is installed, and not a general fuser failure.
If the fuser's sleeve does not spin when you manually turn the gear,
please do not assume that the fuser will not run in the printer. At room