HP LaserJet 2400 Series; Noise in Rear of Fuser

The 2400 series of HP printers are prone to excessive noise in the rear of the machine. Unlike the P3005 engines where, typically, the noise is more gradual and seems to take longer to generate service calls, the 2400 series tends to really develop it’s noise problems at 40,000 to 45,000 copies and it can get extremely bad around 70,000 to 80,000.

In the HP 2400 series printers, while the noise problem appears gradually, it seems to greatly worsen in a short amount of time. I see a lot of service calls generated for this specific problem, unlike with the HP P3005 model where it’s kind of a secondary issue…“Oh yeah, and it seems to be running louder now then when we first purchased it.” I find than many users are afraid to continue to use the 2400 series because it sounds like parts are being destroyed. So identifying the problem in this model is easier and the fix is much more satisfying, because the printer is drastically quieter after it’s been repaired.

What to do on a service call
First, run a few prints, including the configuration page, to check the machine’s usage, overall condition, and its noise level. Then remove the fuser and check out what‘s happening in the rear of the machine, following these directions:

Fuser Removal
Back Cover
1. Open the rear output bin all the way by pressing the door down disengaging the door stops. All the way down the door should be at a 90 degree angle. Remove the two screws.

HP P2400 Series printer remove back cover

2. At the bottom of the back cover behind the dust cover door are two alignment tabs. Disengage those by pulling from the bottom and lifting the cover away from the machine.

HP LaserJet 2400 Series, Remove back cover

I/O Cover
1. Pull right and lift away from machine.
HP LaserJet 2400 Series, IO Cover Removal

1. Remove the fuser-cable cover by releasing one tab on the cover and then rotating the back of the cover toward the center of the printer
HP LaserJet 2400 Series Fuser Removal

2. Remove the duplex inlet guide by releasing the two tabs and pull it out towards you.
HP LaserJet 2400 Series Fuser Removal

3. Disconnect the two cables on the right side and unclip the wire holder on side of frame securing the top cable.
HP LaserJet 2400 Series, Fuser Removal

4. Disconnect the power cable on the left and remove the four screws near the corners on the fuser.
HP LaserJet 2400 Series, Fuser Removal

5. Gently remove the fuser from the back of the machine.
HP LaserJet 2400 Series, Fuser Removal

Note: Pressure roller is on the bottom made out of a rubber like material. The fuser film is on the top and wraps around the heating element.

Alright, with the fuser out, turn it around so the front is facing you. Now, turn it to the right so you’re looking at the gears.

HP LaserJet 2400 Series Roller Gears

The pressure roller gear is the large tan gear

Below the pressure roller gear you will probably see a dark brown pile of bushing dust. In most cases you will also observe the bushing rotated back. On the HP 2400 series the bushing is held in place by a little arm protruding from the bushing and on the end is a little ball that clips into a small hole on the fuser’s metal frame. Due to the intense pressure applied to the pressure roller the bushing likes to unclip from the frame and rotate backwards. Due to the softness of the material of the bushing and the constant rotation of the pressure roller it wears out the inside of the bushing. The end result is the pressure roller and gear moving down and away from the rest of the gears in the rear of the machine, causing more noise and abnormal wear of the surrounding gears.

At first most technicians believed that replacing the fuser or at least replacing the bushings with updated bushings made of a strong material would resolve the issue because everything else appeared to be OK. After doing one of the above fixes and installing the fuser, and in most cases, installing a small spacer between the lower left metal-to-metal screw to secure the fuser would make the noise go away. Unfortunately, this was a temporary fix. Most people wondered why the spacer was needed and they got their answer when the noise returned shortly after the repair, if the spacer was not installed. The spacer allows the fuser to set back a little from its original location. This solved the problem with the teeth on the gears in the rear of the machine having abnormal wear. By moving the fuser back they meshed with the gears but because they were already worn funny they would continue along this path resulting in the noise problem returning within a short period of time.

Check the gears out
With the fuser out, look inside the printer’s cavity and on the left side you will notice four white gears. Three of the gears are on a metal post secured to the machine’s frame with one on an arm swinging between them. The three stationary gears will need to be replaced. In extreme cases the large drive gear, part of the fuser drive assembly in the bottom of the rear cavity, may need to be replaced, (part number RM1-1500). The drive gear rarely needs replacement as the majority of noise issues will be resolved with the fuser and upper gears so I’m not including its removal in this article.

Most people, by now, have already looked at the top three gears and assured themselves after visual inspection that they appear to be OK. But, trust me, they do need to be replaced. Here are the part numbers for the gears:
21-tooth gear (RU5-0377)
20-tooth gear (RU5-0378)
19-tooth gear (RU5-0379)

I’ve taken the time to replace these gears individually. Each one replaced lessens the noise slightly but you will need to replace all of them too fully remove the noise from the rear of the printer.

Alright, since you have the fuser out now and, hopefully, the printed configuration page in front of you, we can further inspect the fuser for other general wear. First, remove the pressure roller gear and check for cracks on the inside where it fits around the roller shaft. Make sure the pressure roller’s surface is smooth and hasn’t developed waves or wrinkles, and check the fuser film for discoloration around the edges or toner buildup on its surface. Check the configuration page for any ghosting and verify the page count. If any of these symptoms are present or the page count is around or above 90,000 and the fuser (Fuser PN RM1-1535) hasn’t been previously replaced, it probably should be replaced at this time.

The Fix
Unlike the HP P3005 printer engine where, if the fuser looks fine with no bushing dust, cracked gears, etc., I typically just replace the gears (which I keep in my car stock) first and go from there, in the HP 2400 series that’s rarely the case. The majority, if not all, will need a new fuser too. If you just have a fuser issue, like a torn sleeve or other fuser issue, when replacing the fuser its best to replace the gears too, even if no noise was present. The gears tend to wear with the fuser so if you just replace the fuser you might find you have a noise where one wasn’t apparent before. Most machines that I’ve serviced had around 50,000 copies when the noise became too much for the customer to handle. With the updated fuser and new gears installed most machines make it another 100,000 to 125,000 prints before more service is required in that area. So, by replacing the fuser and the gears initially you will drastically reduce downtime on the printer, resulting in happy customers or employees. They will know who to call the next time something needs repair.

A side note
The pickup rollers typically show obvious signs of wear at around 50,000 copies so if you just go for the gear replacement you might want to order yourself a cassette tray pickup roller and separation pad. If you decide to replace both the fuser and gears it might be best to just purchase a Maintenance Kit, which includes the pickup rollers, fusing unit and other general maintenance items. This machine doesn’t have a set internal PM counter like some of the higher end models but typically at 125,000 to 150,000 copies PM is advised.

Keeping the customer in mind, companies like Market Point have specifically designed Maintenance Kits to replace the items you would generally find in the higher end models’ kits. Buy purchasing these parts in a kit you reduce their overall cost.
RL1-0568 PICK ROLL Tray1
RL1-0542 PICK ROLL Tray2

And that’s it. Hopefully, you now have a quieter running printer. Keep in mind that, like most models this size, repair vs. replace can become an important decision. The HP 2400 series, unlike others, has very few other known issues. So, once this update is done, future service calls should be relatively few with little being needed except for routine maintenance and the occasional worn pickup roller, which is a relatively inexpensive repair.

With the quality issues of a lot of the more recent printer models, an older printer might be slightly slower but it will most likely be around long after you replace the one you bought for $300…thinking you got a great deal to replace your HP 2400 series printer.

Kevin Gumpp is a certified printer technician and freelance writer for Market Point. If you have a question for Kevin regarding this topic or have any other printer repair related questions or topics you would like more information on, please send an email to maryp@marketpoint.com.

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