@roygore, Thank you for your response.
Since you've already replaced the printhead and even reinserted the original one, we're likely dealing with a firmware or internal printer logic issue, not a hardware printhead fault.
🔄 Let's Do a Semi-Full Reset (specific to HP Photosmart 7520)
This can sometimes clear persistent printhead or ink system errors stored in NVRAM:
⚙️Hidden Service Menu Access:
- Make sure the printer is ON.
- On the touchscreen, press the Back button 4 times quickly.
- This will open a Support Menu.
- (If there's no physical "Back" button, tap the lower-left corner of the screen 4 times quickly.)
- Tap Support Menu→ Resets Menu→ Semi-Full Reset.
- The printer will power off automatically or prompt you to restart.
- After restart, you’ll need to go through the setup process again (language, region, etc.).
⚠️ This reset clears settings and stored error logs but keeps your firmware and usage counts.
💾 Optional: Full Software Reinstallation on Windows 11
After the reset, uninstall any old drivers and reinstall fresh ones:
- Uninstall all HP software via Control Panel > Programs and Features.
- Download the full software from HP (Windows 11 compatible):
- Avoid using "Add a Printer" via Windows Settings — always use HP’s full installer.
✅ After the Reset:
- Try printing a test page from the printer's screen.
- If that works, try printing from your PC.
- If you still get the same error immediately on power-up, even with both printheads, it's likely the printer's logic board or carriage board is failing, and unfortunately, this isn't a user-replaceable part on the Photosmart series.
I hope this helps!
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Take care and have a great day.
Max3Aj
HP Support