11-16-2010 01:52 PM
My office has an HP color laserjet 2840 that 4 of us share for printing. We've all been experiencing various issues with the printer for the past few months. It often will only print the first page of a document and then spit out blank pages after that. When it does print, sometimes it's only the yellow portions of the page, sometimes only magenta, and once it was everything but black. Our IT department said this was happening because it's too cold in our room for the ink to correctly bind to the paper. I'm not buying that answer since it happens both on days that are cold and days that are warm (they seem to have trouble controlling the temperature in our room).
I'm wondering if this is a hardware problem or maybe a driver issue. I believe it started around the time we replaced the toner cartridge and I updated the drivers for the printer. Any ideas?
11-16-2010 03:32 PM - last edited on 04-15-2012 09:03 PM by VidyaVI
Most times the problem is the selenoid that stops the carousel in the correct position to lay down each color for each page. Sometimes the selenoid sticks so the carousel goes past the correct position and hence that color does not print. To repair you have to remove the top scanning and adf and right side covers and the selenoid is located on top on the right side above the right side gears of the carousel. When removed you have to clean the glue residue off the "L" arm. You will also have to put another pad on the "L" arm otherwise the arm becomes magnetized which will make the problem worse. I use a cut down furniture leg pad.
01-03-2012 04:42 AM
I have the exact same problem and am following the required steps to remove the selenoid, but i'm having a hard time identifying what the selenoid looks like. Can you describe or have an image so I know what to remove. I have the HP 2840.
05-16-2012 03:25 PM
Wow. I had been blaming faulty remade cartridges for a while for misc print problems, until an intermittent issue became the yellow only problem described here.
This is not for the faint hearted at all, but the idea of taking the printer to pieces seemed extreme, and I managed a bit of keyhole surgery after taking the left and right side panels off, the front right corner cover, the ADF and then the platen/glass. (some instructions say remove the control panel - don't it is not necessary)
The top cover does not need to come out and can be persuaded into a position just out of the way, without disengaging the prop/ratchet arm.
I only disconnected the obvious cables and hung the screened electronics box/panel by a few cables in order to remove the rotary drive assembly through and out the back, I had to undo the motor at the left hand end, which I left dangling in place. It is a "follow your nose job" in most respects. See file 2840-apart
One of the attached files is a pic of what rotary drive assembly looks like, minus the main motor... the solenoid in question has two yellow wires attached. It seems to reach a state of being semi permanent magnetized after a period if time (5 years in this case) and 3 layers of PVC insulating tape facing he buffer pad builds a big enough gap to prevent it latching spuriously.
It's a ~2 hour job for a first timer. I only have 2 screws left over when it all went back together and worked, so I call that a result. :-)
10-25-2013 12:58 AM
Thanks David & USP.
We've also been blaming the remanufactured yellow cartridge - the printer seemed to be working faultlessly prior to replacement. (The printer was rescued from the tip - the drum had exceeded it's cycle count, fixed using a $9 chip from eBay!)
I considered replacing the felt pad, but opted to use a short length (~10mm) of heat shrink tubing around the L-arm, placed in the pad area. Works brilliantly.
BTW: I removed the top-cover, as I didn't want to break it. It is easy to disengage the prop/ratchet arm - just press small tongue on the gear sideways to release. To rengage ensure the gear shaft is at a counter-clockwise position.
11-02-2013 06:34 AM
I have the same problem and I'm glad to see the solution on this forum. I've been going through the procedure outlined here as well as referring to the 2840 service manual. Unfortunately, I'm having trouble removing the scanner assembly cables (i've only managed to remove one) mainly out of concern I may irreparably damage them. Any tips on where best to grip the connectors (especially the wide non-flat wire cable)? Also, what is the best way to remove/detach ground wires?
I apologize in advance if my descriptions are non-technical as this is not really my expertise. I've included attachments which reference the problems mentioned. Anyway, the information shared on the existing posts are appreciated and I'll keep trying to make this printer work properly.
11-02-2013 08:30 AM
11-02-2013 06:46 PM
Thanks, appreciate the suggestions. I'm just having an issue with the wide wire harness, as you said it is a bit tight. Just want to clarify a little; by gripping it from the wires (the connector doesn't really provide an adequate surface to do so) could I end up pulling the wires from the connector? It has happened to me once or twice.
03-08-2014 11:48 AM
Hi guys, thanks for the tips - I am abotu halfway into the job but I can't figure out how to remove the dark black plastic that is covering the motor assembly - any tips please?
03-08-2014 04:20 PM
03-08-2014 05:54 PM
David, thank you for your reply - I figured it out - the black plastic was the dark portion of the front cover - I needed to remove the lef side cover as well and remove the screw on that side as well.
For others trying some more tips:
After I cleaned the glue I used electrical tape and put the printer back together. I tried ot print a test page and got the scanner error 52. I was ready to give up after reading this is the laser unit but decided to have one more go at it. I noticed that as I was connecting back the ADF connectors I moved one behind the metal unti held by 4 black screws. I re-inserted it and the printer works as new right now. Thank you all ofr your help!
PS - It is a frustrating process but the psoter above was right - go by your nose and you will get it!