LaserJet 2840 - Colour printing issues

[Stevedabeard]

My issue is lack of colour when printing or copying in colour.

I can make print good black & white pages.

I was having blank pages when trying to make copies on the printer and from the PC. I've fitted a new drum to no effect on the issue. I did a demo print from the printers menu and got a good print out, however it was light on magenta and yellow. Then tried another colour copy and got a printout without yellow. I fitted a new yellow toner cartridge as it was showing low but not out. Again this had no effect on the overall problem.

I have been running the maintenance cleaning function regularly to see if that had an effect, none.

My copy printouts now have zero magenta and yellow in the printout.

Any advice on what I can try to make good please?

Thanks in advance.

[Stevedabeard]

The reason I replaced the drum, was that I could hear noises like something was jammed. When trying to turn the drum with the triangular drive thing on the end, it seemed very tight. The new one was stiff, but not as tight as the one I took out.

The jammed noises have reduced.

When indexing the toner caraselle to view each cartridge, the toner is evenly spread over the roller.

[east2100]

Mostly it's so called sticky solenoid's problem which causes the Carousel turns timing wrongly.

Go YouTube finding "HP 2820 HP 2830 HP 2840 Печатает один цвет" & "HP 2820 HP 2830 HP 2840 Prints one color" and you'll find something you want.

[Stevedabeard]

I have now found whilst taking the toner cartridges in and out, the caraselle does not latch in to position to enable the refitting of the cyan cartridge. I will need to investigate further.

[east2100]

It's the same solenoid that makes all these problems which you mentioned.

Check here and hope it helps.

https://h30434.www3.hp.com/t5/LaserJet-Printing/cartridge-carousel-jammed-on-LaserJet-2550L/m-p/7643...

[Stevedabeard · Accepted solution]

After watching loads of videos and stripping the printer, I eventually found the solenoid top right and cleaned up the sticky pad, reassembled and now have full colour.

Thanks for everyone's input;

These videos were very helpful;

https://www.youtube.com/watch?v=NkjSkiDXno0
https://www.youtube.com/watch?v=9BoxmagIjhg&t=1s

[Repairatrooper]

What did you use as a buffer between the two parts of the solenoid to prevent magnetic sticking?

[Stevedabeard]

For the buffer, I used electricians insulation tape as shown in the first video.