HP DeskJet Plus 4120 – continuous blinking after installing cartridges

[kimaau]

Hi everyone,
I have an HP DeskJet Plus 4120 printer that was working fine until recently.
The issue appeared right after I installed original HP 305 cartridges: since then, the printer turns on but stays stuck with the “i” button blinking and the small display flashing without showing anything.

Here’s what I’ve already tried:

• Normal reset and factory reset (X + black copy for 10 seconds).

• Powering on without cartridges, or with only one cartridge installed.

• Direct USB connection to the PC.

• Cleaning the cartridge contacts and the carriage contacts.

• Hard reset by unplugging the power cable for more than 1 minute.

The result is always the same: the printer remains locked and doesn’t allow any operation.

Has anyone experienced a similar issue? Is there any “home fix” for this, or do I have to contact HP support for a replacement (I suspect it might be a logic board failure)?

Thanks in advance for any advice!

[Kuroi_Kenshi]

Hi @kimaau,

Welcome to the HP Support Community!

Thanks for reaching out!

We're thrilled to have the opportunity to assist you and provide a solution.

I understand your HP DeskJet Plus 4120 is turning on but getting stuck with the blinking “i” button and flashing display right after installing the cartridges. Let’s go through a few steps to check what could be causing this.

1. Check Power Source

Ensure the wall outlet is working by plugging in another device (like a lamp or phone charger).

If you’re using a surge protector or extension cord, try connecting the printer directly to the wall outlet.

2. Verify Power Cord & Adapter

Make sure the power cord is firmly connected at both ends.

Check for any damage, unusual heat, or loose connections.

3. Power Button Test

Hold down the power button for 10–15 seconds, release, and then press it once again to try turning it on.

4. Check for Power Indicators

Observe the “i” button and display lights.

Listen for any internal sounds like motor or cartridge movement.

5. Remove Cartridges and External Devices

Power off the printer and remove both cartridges.

Disconnect any USB cables or external accessories.

Power on the printer to see if the blinking persists.

6. Perform a Hard Reset

Unplug the power cord from the wall and the printer.

Press and hold the power button for 15 seconds to drain residual power.

Reconnect only the power cord and turn on the printer without cartridges.

7. Reinstall Cartridges Carefully

With the printer on, install one cartridge at a time: first black, then tri-color.

Ensure cartridges click firmly into place and the contacts are clean.

8. Check for Firmware Updates

If the printer can power on with cartridges installed, connect it to a PC or HP Smart app.

Check for firmware updates, as outdated firmware can cause startup lockups.

I hope this helps.

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Best regards,