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Brother MFC-J4420DW Capacitor Replacement

What you need

  1. Brother MFC-J4420DW Capacitor Replacement, Removing hood holder: step 1, image 1 of 3 Brother MFC-J4420DW Capacitor Replacement, Removing hood holder: step 1, image 2 of 3 Brother MFC-J4420DW Capacitor Replacement, Removing hood holder: step 1, image 3 of 3
    • Disconnect the power cord of the printer

    • Open the printer as you would to access the USB port.

    • Pull out the rear end of the hood holder (see picture two). After that you can remove the top part of the hood holder.

    • Now remove the hood holder completely.

    • It is quite useful to put the printer near something so that you can lean the top against something, for example a wall.

  2. Brother MFC-J4420DW Capacitor Replacement, Removing cables connected to the top part of the printer: step 2, image 1 of 3 Brother MFC-J4420DW Capacitor Replacement, Removing cables connected to the top part of the printer: step 2, image 2 of 3 Brother MFC-J4420DW Capacitor Replacement, Removing cables connected to the top part of the printer: step 2, image 3 of 3
    • Next remove the cover on the left side of the printer (lift the right side of the cover first).

    • Unplug the black ribbon cable, the blue and the white plugs from its sockets and unscrew the cable which is attached with a screw (see second image)

    • Remove the red and white plugs from its sockets as shown in picture three.

  3. Brother MFC-J4420DW Capacitor Replacement, Remove the top part of the printer: step 3, image 1 of 3 Brother MFC-J4420DW Capacitor Replacement, Remove the top part of the printer: step 3, image 2 of 3 Brother MFC-J4420DW Capacitor Replacement, Remove the top part of the printer: step 3, image 3 of 3
    • Flip the plastic part shown in picture one up to the top part of the printer

    • Now you can easily remove the top of the printer by pushing it away from the printer (not up).

  4. Brother MFC-J4420DW Capacitor Replacement, Remove cover: step 4, image 1 of 2 Brother MFC-J4420DW Capacitor Replacement, Remove cover: step 4, image 2 of 2
    • Remove the screws connecting the black plastic cover to the printer (see image)

    • Remove the cover

  5. Brother MFC-J4420DW Capacitor Replacement, Remove metal cover: step 5, image 1 of 3 Brother MFC-J4420DW Capacitor Replacement, Remove metal cover: step 5, image 2 of 3 Brother MFC-J4420DW Capacitor Replacement, Remove metal cover: step 5, image 3 of 3
    • Remove the little PCB as shown in image one by lifting it up. Be careful not to damage the pins connecting the PCB with the motherboard

    • Unscrew the two screws fixing the metal cover to the motherboard as shown in picture two.

    • Remove the metal cover to get full access to the motherboard

  6. Brother MFC-J4420DW Capacitor Replacement, Replacing the capacitor: step 6, image 1 of 2 Brother MFC-J4420DW Capacitor Replacement, Replacing the capacitor: step 6, image 2 of 2
    • On the right side of the motherboard there is a coin shaped capacitor. In picture two you can see a detailed view of the capacitor (5.5V 0.22F).

    • Note which polarity of the capacitor is facing which side on a piece of paper.

    • You can find the + and - Symbols on the legs of the capacitor.

    • Remove the capacitor.

    • The Brother technician used side cutters to remove the defect capacitor.

    • Be careful to LEAVE ENOUGH OF THE WIRE to be able to solder a new capacitor onto them.

    • Looking at you piece of paper, solder the new capacitor in THE RIGHT DIRECTION (POLARITY) to the remaining wires from the removed capacitor.

    • Using the steps above in reverse, reassemble the printer.

    • After reassembling the printer, reconnect the power cord.

    • The first few times you start you may encounter the same behaviour as before the repair. After two or three restarts my printer worked fine again.

    • I hope this guide helps. Happy repairing. If something is unclear or you have suggestions how to phrase things better (engl. is not my mother tongue) please leave a comment.

Finish Line

34 other people completed this guide.

Matthias Loikasek

Member since: 11/24/16

1,224 Reputation

1 Guide authored

40 Comments

How does one make sure that the new capacitor lasts longer than the original? This doesn’t look like a procedure I would want to repeat every 2 years. Did Brother use low quality capacitors on these printers? I don’t know how to tell if a capacitor is low quality or high quality.

piddien - Reply

I could imagine that the voltage tolerances are a bit wider than the maximum 5.5V the capacitor is specified for. So I would go for a 6+V 0.22F cap if it is available in the same housing.

joerg albert -

try to use a higher capacity e.g. 1F, that might last longer.

Juergen Klute -

Fabulous guide, thank you! Used on my MFC-J4510DW. I went as far as removing the printed circuited board all the way to be able to properly de-solder the failed capacitor and then put the new capacitor legs in the thru-holes on the board. Else the capacitor would sit too high and the metal shield over the board would not fit. The new NEC capacitor is considerably bigger (still 5.5V 0.22F). Hopefully it will last longer. I’m hoping it will also fix the WiFi disconnection problem that is often reported. So far, so good.

Vincent de Rooij - Reply

Brilliant advice and clarity for the repair. My MFC J4420DW won’t power up and all the indicators suggest the ‘power supply’ is faulty.

Does anyone know if I change the Capacitors on this board, will it resolve the issue? Any comments extremely appreciated.

Paul Keegan - Reply

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