Formatter (Video Interface) PCB Assembly: p/n C3125-67901
This is the latest revision 5Si formatter. It includes a fuser temperature control code that earlier formatters do not, and it is recommended for use in the HP LaserJet 5Si series.
(See revision notes below for further details on this formatter and earlier revisions)

Earlier versions of the HP LaserJet 5Si formatter (p/n C3168-67906)
   (See also notes below for details on the most recent version, C3125-67901)

There are six revisions of the 5si / 5siMX / 5siNX printer formatters. The difference is the revision level of the firmware located in masked ROM chips. These chips are soldered to the main formatter board and cannot be changed easily. Therefore, if you would like to upgrade the firmware, it's best to purchase a whole new formatter board (C3168-67906).

The firmware revision level can be found by printing a configuration page from the printer control panel printer menu. The table below maps the formatter part number to the firmware revision. If you printer is unable to print the configuration page, you can also read the part numbers on the IC. We also list the part numbers of the firmware and map them to the formatter part numbers in the table below.

Date Code 19980203 V.9.95
Date Code 19961220 V.9_7
Date Code 19960829 V.9_1

The three earlier revisions of the C3168-67906 formatter have known problems, and we don't stock them. These revision numbers are listed below.

Date Code 19960401 V.8_6
Date Code 19960208 V.8_5
Date Code 19950711 V.7_9

There is no PCL menu in these revision formatters. You can determine the revision number on the formatter by printing a test print page, or looking in the control panel menu.

•••>To determine which revision formatter you have without printing a test page,
        look up your ROM part numbers in the table below.

P/N C3125-67901, the most recent version of the LaserJet 5Si formatter:
   (See also notes above for details on the earlier versions)

The C3125-67901 formatter, pictured above, was originally made for the latest version of the 5Si, the HP LaserJet 5si HM (Heavy Media ) printer. The C3125-67901 includes a fuser temperature control code that effectively upgrades the 5Si HM formatter and puts the 5Si on a par with the series that replaced it, i.e. the HP LaserJet 8000 series. (The LJ 8000 series uses the same engine and printer body as the 5si series, the difference between them being the control panel and the formatter). The temperature contol code allows the printer to achieve a higher fuser temperature, which provides better printing on a wider variety of media, including heavier weight card stock.

Even though the 5si HM formatter indicates it is rev V. 9_7, making it appear lower than the C3168-67906 V. 9.95 for the 5si series, C3168-67906 does not include the fuser tempurature control code.

We have tested this 5SI HM formatter with the earlier 5Si models: 5Si, 5SiMX, 5SiNX, and Mopier 5Si, and it is compatible with all of them. Therefore, if you are replacing the formatter in your earlier model 5Si, and wish to upgrade it, we reccomend the HM formatter, C3125-67901.

For your information, we list below HP's productions dates for 5Si series printers: