HP 2840 prints blank pages or yellow only (26038 Views)
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Registered: ‎11-16-2010
Message 1 of 30 (26,038 Views)
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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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Message 2 of 30 (25,956 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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Message 3 of 30 (25,730 Views)

Re: HP 2840 prints blank pages or yellow only

David post did the trick. Thanks.

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Registered: ‎01-03-2012
Message 4 of 30 (24,984 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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Message 5 of 30 (24,975 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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Message 6 of 30 (24,736 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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Registered: ‎05-16-2012
Message 7 of 30 (24,633 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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Message 8 of 30 (19,924 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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Registered: ‎11-02-2013
Message 9 of 30 (19,755 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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Message 10 of 30 (19,746 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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Registered: ‎11-02-2013
Message 11 of 30 (19,718 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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Registered: ‎11-02-2013
Message 12 of 30 (19,711 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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Message 13 of 30 (15,361 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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Message 14 of 30 (15,351 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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Registered: ‎07-17-2007
Message 15 of 30 (15,334 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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Registered: ‎07-14-2014
Message 16 of 30 (12,236 Views)

Re: HP 2840 prints blank pages or yellow only

Where do I get the replacement PAD from?

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Message 17 of 30 (12,223 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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Registered: ‎10-17-2014
Message 18 of 30 (9,390 Views)

Re: HP 2840 prints blank pages or yellow only

First of all I want to thanks the posters. Because of these posts I don't have to buy a new printer.

 

I removed up to the "top cover assembly" (see HP Color LaserJet 2820/2830/2840 service manual, page 162) and did not disassambled the selenoid. I have cleaned the metal plate that is attrackted by the "L" arm and clued on the "L" arm a small piece of plastic (from a bank card).  Be sparing with clue to prevent glue also comes on the metal plate that is attrackted by the "L" arm . The wooden stick on the picture "Small piece of plastic glued on "L" arm" is only used to hold the plastic piece in place during the drying of the glue.

 

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Registered: ‎11-01-2014
Message 19 of 30 (8,441 Views)

Re: HP 2840 prints blank pages or yellow only

OK, So having found the site, and changing the solenoid, I now have blank sheets where they were previously yellow.  Any ideas?


WimHolland wrote:

First of all I want to thanks the posters. Because of these posts I don't have to buy a new printer.

 

I removed up to the "top cover assembly" (see HP Color LaserJet 2820/2830/2840 service manual, page 162) and did not disassambled the selenoid. I have cleaned the metal plate that is attrackted by the "L" arm and clued on the "L" arm a small piece of plastic (from a bank card).  Be sparing with clue to prevent glue also comes on the metal plate that is attrackted by the "L" arm . The wooden stick on the picture "Small piece of plastic glued on "L" arm" is only used to hold the plastic piece in place during the drying of the glue.

 


 

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Registered: ‎02-27-2006
Message 20 of 30 (8,426 Views)

Re: HP 2840 prints blank pages or yellow only

First off what do you mean by changing solenoids? The procedure above cleans the original part and has material put down to replace the worn material. When the solenoid is installed correctly you should not be able to turn the carousel as it will be locked in place. If you stick a small flat object under the "L" arm to raise it, then the carousel will turn. In other words if the solenoid is installed wrong, is not the correct solenoid or the spring is missing from the "L" arm, the printer will not function correctly. Take a closeup picture of the solenoid and post it here so we can see if it is right.
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Registered: ‎12-31-2014
Message 21 of 30 (5,383 Views)

Re: HP 2840 prints blank pages or yellow only

This fix absolutely works.  Took three hours.  I diasembled the top section and most of the right hand side just to get to the selenoid.  I used the "bank card method" since the previous poster does not discuss the gap measurement using a "furniture pad" .  Reassembly was a breeze as I phographed step-by-step the entire disasembly and just viewed the photos in reverse order,  No screws left over.  The printer now works perfectly.  One note to take away.... there was no reference as to the type of "glue" to use.  I considered using epoxy, but instead chose a Cyanoacrylate (super glue) brushed on like finger nail polish and it should hold well enough.  If not, I'm confident that I can reaccomplish this reapair in about an hour. 

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Registered: ‎01-08-2015
Message 22 of 30 (4,669 Views)

Re: HP 2840 prints blank pages or yellow only

Hi there I did this fix and all went perfect and then when turning on again it says "Incorrect Yellow".

Any ideas what I may try to fix this?

Could the new pad be made slightly too thick?

I have checked all the wires and conections.

It will rotate the gears to all the colours with no cartridges installed but when you intall a colour it will not move to the next colour even though you hear it make the motion. I have tried every colour.

I also tried reseting to default settings from the control panel.

I tried releasing the gears manually and installing all colours and turning the machine back on.

All done so far with no luck.

Help please.

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Registered: ‎01-08-2015
Message 23 of 30 (4,660 Views)

Re: HP 2840 prints blank pages or yellow only

Ok, stripped machine back down and halved the thickness of the new pad to about the size of a credit card. Reasembled and what do you know, everything works great and the problem with printing blanks has all been resolved.

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Registered: ‎03-16-2008
Message 24 of 30 (3,669 Views)

Re: HP 2840 prints blank pages or yellow only

Just wanted to say thanks to all who have posted in this topic. Just repaired mine.

 

I have to say it was a lot easier than I expected from the posts here. Most parts just unclip, plus there are a few screws.

 

Sure it took a long time but I had the service manual to help me so it wasn't too bad. I imagine this takes minutes if you're a professional. I took the complete rotary drive assembly out and removed the solenoid - this is about 4 screws and only takes a moment. Makes the job much easier.

 

I used the electrical insulating tape technique, and placed 4 layers where the felt pad used to be.

 

I also got the scanner error 52 so had to remove a few parts and rejig cables to get rid of that, which took another 30 minutes - that's all.

 

Now it prints a demo page - whether it works in anger is yet to be seen!

 

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Message 25 of 30 (3,642 Views)

Re: HP 2840 prints blank pages or yellow only

A few tips. (a) Know the names of the parts. For example, formatter is the steel cage you have to remove, rotary drive assembly is the little frame with the motors and the target solenoid. Scanner (important if you get error 52) refers not to the document scanner but the laser unit connected by a flat cable that you have to remove to get to the rotary drive assembly. Top cover, right cover, left cover, left front cover, right front cover, left rear cover, right rear cover are self-explanatory. So are ADF and I/O cover.

 

(b) Each time you remove a part put the screws somewhere safe (into labelled component bags if you have them, or somewhere you can identify them later).

 

(c) Each time you remove a part number it (with an indelible marker) on the inside. Then if your memory is like mine, you just follow the numbers in reverse to install them.

 

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