Loud click in hinge when opening top lid

[NoMeatoBurrito]

HP OfficeJet Pro 7740.  When I open the top lid, say when I want to put a document on the glass for scanning, the right rear hinge (right side as I look at it from the front of the printer) makes one loud *CLICK* noise when the lid is about 15 degrees open, and the lid jerks upwards slightly right when the click happens.  It does this every time I open the lid.  

I do not see any debris or other obstruction inside the hinge that might be causing it, and I do not see any cracks in the plastic or any other visible defect.  

[VikramTheGreat]

Hi @NoMeatoBurrito,

Welcome to the HP Support Community.
 

Thank you for posting your query. I will be glad to help you.

I know how concerning it can be when a trusted device like your HP OfficeJet Pro 7740 starts behaving unexpectedly. From your detailed description — a sharp click sounds and a slight jerk upwards around the 15-degree mark when opening the scanner lid — this suggests the issue may involve:

• A stiff or misaligned tension spring inside the hinge mechanism (often under tension to help hold the lid open),
• Or a possible internal guide rail catch momentarily binding, then releasing.

Even though you don’t see any cracks or debris, and kudos for checking closely.
 

1. Inspect with a Flashlight

With the printer powered off and unplugged, carefully open the lid again. Use a bright flashlight to get a better look inside and around the right hinge (you may need to tilt the printer slightly for a better view — safely, of course).

You're looking for:

• Any worn plastic, rub marks, or deformed components near the hinge?
• A spring that may have shifted out of alignment.

2. Compare Both Hinges

Open the lid slowly and observe both sides:

• Does the left hinge move more smoothly?
• Does the right side seem tighter or "lag" slightly behind?

If yes, this suggests internal tension may not be balanced, which could cause that audible pop as the stress releases.

3. Reset the Printer

Sometimes, mechanical calibration can get thrown off. Try this:

• Turn the printer off and unplug it completely (including from the wall).
• Leave it unplugged for about 2–3 minutes.
• While unplugged, gently open and close the lid a few times to reset any mechanical latching mechanism.
• Plug it back in and power it on.

4. Scan Function Test

If scanning still works normally, and you don't see alignment issues or performance degradation, the issue may be cosmetic/mechanical but not critical. However, it’s good to monitor for worsening sound, stiffness, or resistance.

I hope this helps.

Take care, and have an amazing day!
 

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Regards,

VikramTheGreat