Archived from groups: comp.periphs.printers (More info?)
"Colliermeister" <firstname.lastname@example.org> wrote:
>HP Laserjet 4500n
>The manual don't list the error codes. Help anyone ?
Indicates that a critical firmware error has occurred.
An invalid command or data was sent to the
formatter causing the processor to stop. This is the
last action taken by the processor. The most likely
cause of this error is invalid data or a bad command
which was sent to the printer. A poor quality parallel
cable, connection, or home grown application have
been known to cause this error.
1 Verify that all cables are connected.
2 Turn the printer off and on to reset the printer.
3 Cancel all print jobs then resend. Try to isolate
any offending print job.
4 If the formatter pan assembly or DC controller
was removed, make sure the ribbon cable
between the DC controller and the interconnect
PCB is connected.
Table 7-2 Numerical printer error messages (continued)
EN Chapter 7 Troubleshooting 233
50.X FUSER ERROR
The fusing assembly contains two heating bulbs,
two thermo-switches, and two thermistors.
AC power is provided to the fusing assembly via the
DC power supply which is controlled by the
DC controller PCB. The thermistors monitor the
temperature of the fusing assembly and provide
feedback to the DC controller PCB to regulate the
fusing temperature. The two thermo-switches are
wired in series with the fusing bulbs and “open” if
the temperature exceeds 240° C.
1 Low temperature error
2 Fuser warm-up service
3 High fuser temperature
4 Faulty fuser
5 Fuser voltage mismatch (verify that you have
NOT installed a 110V fuser in a 220V printer or
6 Fuser heater cutoff
7 Fuser motor malfunction (see recommended
action for 50.7 Fuser error).
Note A visual check to determine if
the fusing assembly is
functional can be made by
defeating the rear door interlock
switch (see Figure 7-28) by
pressing in on the white plastic
above the left rear corner of the
fan and then powering on the
printer. If the fusing bulbs and
thermo-switches are good, you
should observe light from the
lower fusing bulb as the printer
1 Turn the printer off and on to reset the printer. If
the error persists, try re-installing the fusing
assembly. If the error continues to persist,
proceed to step 2.
2 Turn the power off and remove the fusing
assembly. Measure the resistance between pin
3 and pin 4. The resistance should be between
6+/-2 ohms. If there is no continuity between
pins, it may be assumed that either a heating
bulb and/or a thermo-switch is “open”. Replace
the fusing assembly. If resistance limits were
acceptable, proceed to step 3.
3 Referring to Figure 7-31, measure the
resistance for both the upper and lower
thermistors. The resistance should be between
430K ohms and 310K ohms at room
temperature (25° C). If the resistance exceeds
limits, replace the fusing assembly. If resistance
is within limits proceed to step 4.
4 Verify the connectors at J1011 of the DC
controller PCB and J1 of the Low voltage power
supply assembly are firmly seated.
5 Replace the power supply assembly.