Scan bar flashing on HP Smart Tank 720

[Trebla247]

Brand new HP Smart Tank 720

After successful installation instructions, I noticed a persistent flashing light from the scan bar. It is even visible with the scan bed lid closed, when looking carefully.

Searched around for similar cases. Found several. Notably:

- https://youtu.be/WjEZJQPRwXo?si=JZ6oeo6ONncM-GXS

- https://h30434.www3.hp.com/t5/Scanning-Faxing-Copying/Scanning-bar-light-constantly-flashing/td-p/76...

- https://h30434.www3.hp.com/t5/Printing-Errors-or-Lights-Stuck-Print-Jobs/HP-DESKJET-4255E-Scan-Bar-F...

I tried the power cycle suggestions. Did not resolve issue.

I tried a different power cable. Did not resolve the issue.

I successfully upgraded the factory firmware (SAYAWLPP1N001.2215A.00) over the network from a Windows 11 PC using the latest available firmware on the HP Support website (SAYAWLPP1N002.2450A.00). Did not resolve the issue.

Power cycled again. Did not resolve the issue.

Interesting observation is that prior to the firmware update, the EWS-based firmware update feature was non-functional due to a claimed network problem. After the update the EWS-based firmware update feature became responsive and reported that the newly updated firmware is indeed the latest.

Another interesting observation is that the 1 year "factory warranty" associated with the printer's serial number is indicated online as having commenced on 31 October 2024. I bought the printer online from an authorised seller, brand new on 4 August 2025 and received and installed it yesterday on 8 August 2025.

The flashing scan bar doesn't inconvenience or irritate me. I am however concerned that it doesn't seem normal and may contribute to premature failure or degradation of the scanning capability in time, which seems otherwise fine at the moment.

Is this normal?

Will a replacement printer of the same model also exhibit this strange flashing scan bar?

[Hawks_Eye · Accepted solution]

Hi @Trebla247 

Welcome to the HP Support Community! We're here to help you get back up and running.

Thanks for the thorough explanation — you've done excellent diagnostic work already, including firmware updates, multiple restarts, and even checking other user reports. Based on your findings and current behavior, here’s a clear breakdown of what's happening:

Is the flashing scan bar on the HP Smart Tank 720 normal?

Yes, to a certain extent, this behavior is expected and normal in several HP printer models, including some units in the Smart Tank, DeskJet, and ENVY series. The scan bar may periodically emit light (faint blinking or pulsing) when the printer is in an idle, standby, or network-connected state. This does not necessarily indicate a hardware fault.

The function serves low-power readiness checks or calibration routines. It does not engage the full scan motor or scanning process, and the light level is usually very low.

Will a replacement unit behave the same?

Most likely, yes. Several users who've had replacements or exchanged units report identical behavior. It appears to be a design aspect of the scanning hardware or firmware in this model line, not a production defect.

Regarding Warranty Start Date Discrepancy:

HP typically estimates warranty based on manufacture or shipment date, not the retail purchase date. But you can correct it:

Go to the Product Warranty Check website. https://support.hp.com/us-en/checkwarranty

Select the country/region where the computer was purchased, type your serial number, and then click Submit.

1. From the HP Product Warranty Check results for your product, click Dispute this to display the Warranty validation form.

2. Type your contact information, and then select a Dispute reason.

3. If prompted to upload the proof of purchase, click Choose File, and then double-click the proof of purchase file to upload it.

Note: Make sure that the file does not exceed 2 MB and is an acceptable digital file format: .bmp, .doc, .docx, .gif, .jpg, .png, .pdf, or .zip.

4. Click Dispute warranty.

HP reviews the warranty status for your product and contacts you after the review.

Reference link: https://support.hp.com/us-en/document/ish_2534210-1364541-16

Summary

The scan bar's faint blinking is not a fault, and you're not alone in noticing it.

It’s not known to cause long-term damage or impact scanning quality.

A replacement printer would likely behave the same.

Your warranty can be corrected by submitting proof of purchase online.

If my response helped, please mark it as an Accepted Solution! ✅ It helps others and spreads support. 💙 Also, tapping "Yes" on "Was this reply helpful?" makes a big difference! Thanks! 😊

Take care, and have an amazing day!

Regards, 

Hawks_Eye

[Hawks_Eye]

@Trebla247 A huge thank you for marking this post as the 'Accepted Solution'! We're thrilled that we could help resolve your issue. 

If you have any more questions or need further assistance, please don't hesitate to ask. We're here to help! 

Thanks again for your confirmation, and we wish you an amazing day ahead! 😊

Regards, 

Hawks_Eye