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Canon LBP 2900 Printer Repaired

By on May 15, 2022
laserjet printer repair







canon laserjet printer repair

Fault Symptom: Some portion of printing is missing from printout.

printer print wording missing

Most of time this problem is because of Toner Cartridge may run out of the toner ink. But some other factor may also cause like Bad imaging drum in cartridge, Bad Scanner Unit, Dust on scanner Lens, defect ECU Unit, Bad ECU Cables, Bad Fuser Unit and many more reasons are involved.

In this model self-test is possible only when printer is connected to the PC (other Models do have self-Test facility without connected to the PC). So re confirming the problem I took self test print out from my PC & got print out as sample photo given above.

So first step I replaced the working toner cartridge and took the print out but same problem that means cartridge is Ok & problem is with some other section in the printer. Now it required visual inspection by section wise as stated above. So I started dismantling the printer.

how to dismantle laserjet

canon laserjet card repair

how to fix a broken laserjet canon printer

Opened fuser unit to check the Fuser Heater sleeve seems Ok.

Then opened scanner unit cleaned the lens & Mirror.

cleaning laserjet lens

how to clean canon laserjet lens

After cleaning process I reassembled the Printer & took the printout this time I got satisfactory Printout.

canon laserjet printer repair

So here I found Cause of the problem was dust on the Focus lens & Mirror on the scanner motor inside the scanner unit.

yogesh panchal

This article was prepared for you by Yogesh Panchal who works as a Computer Hardware Engineer in Mumbai India.

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Note: You can check his previous repair articles on LED Torch Repaired




  1. Albert van Bemmelen

    May 15, 2022 at 6:00 pm

    I know from experience how much I dislike opening these mostly large office laserprinters. So hats off to you for accomplishing such a nerve wracking task and for fixing these dreadful printers. Why I only use 2 identical Brother inkjet printers at home. Which never needs any toner and neither produces nasty ozone.

    • Yogesh Panchal

      May 16, 2022 at 1:07 am


      Now a days in this type of repair we required some working parts in spare for the troubleshooting.

    • Marco

      May 18, 2022 at 3:44 pm

      I really hate inkjet printers: every time you need it, the cartridge head is dry and blocked..very annoying..

      • Yogesh Panchal

        May 19, 2022 at 11:15 pm

        Inkjet Printers are good if you have continuous printing workload infect also now a days you have choice of larger Ink tank option printer available in the market.
        Ink get clog because liquid Ink is made for fast drying & it will get clog if your printer is not in use at least once in a week.

  2. Parasuraman S

    May 15, 2022 at 7:01 pm

    Very useful article! Gives inspiration to open and try to solve problems, as I never have set my hand on any of these!

    • Yogesh Panchal

      May 16, 2022 at 1:16 am

      you can do it sir, just need a knowledge of working process of the equipment.

  3. Arun Kumar

    May 15, 2022 at 7:09 pm


    • Yogesh Panchal

      May 16, 2022 at 1:16 am

      Thanks! Arun kumar

    • Yogesh Panchal

      May 19, 2022 at 11:16 pm

      Thanks!Arun Kumar

  4. Waleed Rishmawi

    May 15, 2022 at 8:45 pm

    Hats off to you my friend. A very good repair information. Thanks for sharing

    • Yogesh Panchal

      May 16, 2022 at 1:17 am


    • Yogesh Panchal

      May 19, 2022 at 11:17 pm

      Thanks! Waleed

  5. Anwar Shiekh

    May 15, 2022 at 10:18 pm

    I would tend to try blast such duty units with a powerful blower such as the DataVac

    • Yogesh Panchal

      May 16, 2022 at 3:24 pm

      Thanks! Anwar shiekh

  6. Lynn Blakely

    May 15, 2022 at 10:51 pm

    Dear Sir Yogesh: Thanks for an informative article, I have never done any repair on a printer. I recommend Brother printers, even though I use HP. none of those are laser however.

  7. Yogesh Panchal

    May 16, 2022 at 3:27 pm

    Lynn Blakely,
    Thanks! for your comment.Laser printer is required dust free area because every thing is depends on sensors.


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