HP 2840 prints blank pages or yellow only (15023 Views)
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Occasional Visitor
sabriel7
Posts: 1
Registered: ‎11-16-2010
Message 1 of 17 (15,023 Views)

HP 2840 prints blank pages or yellow only

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?

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Outstanding Contributor
DavidZuts
Posts: 15,117
Registered: ‎02-27-2006
Message 2 of 17 (14,990 Views)

Re: HP 2840 prints blank pages or yellow only

[ Edited ]

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.  

 

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Javier Villa
Posts: 2
Registered: ‎01-10-2011
Message 3 of 17 (14,768 Views)

Re: HP 2840 prints blank pages or yellow only

David post did the trick. Thanks.

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Todo1997
Posts: 1
Registered: ‎01-03-2012
Message 4 of 17 (14,022 Views)

Re: HP 2840 prints blank pages or yellow only

Hi,

 

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.

 

Thanks

 

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Outstanding Contributor
DavidZuts
Posts: 15,117
Registered: ‎02-27-2006
Message 5 of 17 (14,010 Views)

Re: HP 2840 prints blank pages or yellow only

See the attached.  The item next to the screwdriver is the solonoid.

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p_latini
Posts: 1
Registered: ‎04-13-2012
Message 6 of 17 (13,773 Views)

Re: HP 2840 prints blank pages or yellow only

David, you are the man. Thanks for sharing. This fix worked perfectly for the problem mentioned in the subject.

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USPnet
Posts: 1
Registered: ‎05-16-2012
Message 7 of 17 (13,667 Views)

Re: HP 2840 prints blank pages or yellow only

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. :-)

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dav1d beard
Posts: 2
Registered: ‎11-09-2008
Message 8 of 17 (8,962 Views)

Re: HP 2840 prints blank pages or yellow only

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.

 

 

 

 

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wordpass
Posts: 3
Registered: ‎11-02-2013
Message 9 of 17 (8,793 Views)

Re: HP 2840 prints blank pages or yellow only

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.

 

Thanks!

 

j

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Outstanding Contributor
DavidZuts
Posts: 15,117
Registered: ‎02-27-2006
Message 10 of 17 (8,782 Views)

Re: HP 2840 prints blank pages or yellow only

Just pull them out. You can apply a bit of force that is necessary. For flat ribbon cables just pull. For wire harnesses, grab all the wires near the connector and pull it out. If real tight just move it back and forth a little and it will come out. For the grounding wire just use a small needle nose pliers to grab the end and pull away.
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wordpass
Posts: 3
Registered: ‎11-02-2013
Message 11 of 17 (8,756 Views)

Re: HP 2840 prints blank pages or yellow only

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.

 

Thanks.

 

J

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Visitor
wordpass
Posts: 3
Registered: ‎11-02-2013
Message 12 of 17 (8,749 Views)

Re: HP 2840 prints blank pages or yellow only

Ok, I got it. Sorry about that, had to work up the courage. As previously said, not for the faint of heart.
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Tomas Vetrovsky
Posts: 3
Registered: ‎07-17-2007
Message 13 of 17 (4,397 Views)

Re: HP 2840 prints blank pages or yellow only

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?

 

2014-03-08_11-46-59.png

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Outstanding Contributor
DavidZuts
Posts: 15,117
Registered: ‎02-27-2006
Message 14 of 17 (4,387 Views)

Re: HP 2840 prints blank pages or yellow only

No idea what black plastic piece you are talking about. I do not remember there being one. Take a picture with your phone and post so we can see what you are talking about and if you are going about this in the right way.
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Tomas Vetrovsky
Posts: 3
Registered: ‎07-17-2007
Message 15 of 17 (4,370 Views)

Re: HP 2840 prints blank pages or yellow only

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!

 

2014-03-08_17-45-49.png

 

2014-03-08_17-49-53.png

 

 

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raige
Posts: 1
Registered: ‎07-14-2014
Message 16 of 17 (1,272 Views)

Re: HP 2840 prints blank pages or yellow only

Where do I get the replacement PAD from?

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Outstanding Contributor
DavidZuts
Posts: 15,117
Registered: ‎02-27-2006
Message 17 of 17 (1,260 Views)

Re: HP 2840 prints blank pages or yellow only

Just use a thin velcro pad or thin furniture pad. If neither available use some electrical tape.
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