@tigerlover, Welcome to HP Support Community.
Thank you for posting your query, I will be glad to help you.
That sounds extremely frustrating — especially for an all-in-one device that should just work when you need it. Since you’ve already gone through all the HP-recommended steps and the device is:
- Powering on by itself
- Printing gibberish or random characters
- Not responding to the power button
- Generally not functioning normally
It’s safe to say this is a hardware-level failure — possibly related to the printer's logic board (formatter board), firmware corruption, or internal circuitry. Here’s what you can do next:
✅ Double-Check These (If Not Already Done):
Power Reset (Hard Reset):
- Disconnect the printer from power and USB/Ethernet cables.
- Wait at least 2–3 minutes.
- Press and hold the Power button for 20 seconds (if it still won’t shut off, just wait).
- Plug it back in and see if the behavior persists.
Isolate From Network:
- If it keeps printing unknown letters, it might be receiving rogue print jobs.
- Try starting it completely disconnected from your Wi-Fi/Ethernet/USB and see if the gibberish continues.
USB Device Malfunction:
- A corrupted print queue from a PC can trigger odd jobs. Clear the print queue on your PC.
- Disable all HP printers from Settings > Printers & Scanners, then reconnect manually once you've reset things.
📝 Bonus Tip:
If you’re still dealing with random printing, remove the printer from all your devices:
- Go to Devices and Printers→ Right-click and Remove device.
- Clear your print spooler:
- Open Command Prompt (Admin) and type:
net stop spooler
del %systemroot%\System32\spool\printers\* /Q
net start spooler
- Open Command Prompt (Admin) and type:
I hope this helps.
Take care and have a good day.
Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping!
Max3Aj
HP Support