HP officejet 6958 can not detect end of scan

[WalkingPenguin]

This is the same issue that has been asked many times before. Quoting from previous old posts

My HP OfficeJet 6958 All-in-One has an issue when scanning documents via the automatic document feeder.

My document or documents feed fine, but the scanner does not seem to be able to detect the end of the document. When scanning a single page document the document feeder continues to run and run even after the single page has been fully scanned. When scanning a multi-page document, the document feeder picks up page after page successfully, but after the final page fully runs through the scanner, the document feeder continues to run and run. In both scenarios (single page or multiple pages), after the final page has run through the feeder, the feeder continues to run and ultimately results in an error.

On the small touchscreen of the printer itself, I get the following error message:

The document feeder was not able to pick up the original. Make sure the document feeder cover is closed completely, load the original in the document feeder, and try again.

As previously stated, these errors occur after the last page has been fed through the feeder. It looks like the scanner/feeder is having trouble identifying the end of the document.

I am using 8.5x11 paper and I have tried performing the reset by disconnecting the power for 60sec while the printer is on.

Many thanks in advance!

[WalkingPenguin · Accepted solution]

I resolved this issue by fixing a broken wire that runs from the ADF to the central processing unit. The wire, by my guess, feeds the CPU on the status of the automatic paper feeder. When it is damaged/broken, the CPU can not determine the status of the document feeder and continues to "search" for additional pages, until it times out and eventually results in a cancelled scan.

The wire location is near the backside of the "hinge" when you open the scanner top to access the glass flatbed. Viewing from the top, it is on the upper left corner. See attached picture. The wire somehow becomes jammed between the hinges. As time goes by, it was worn off and broken apart by the mechanical movement of the hinges, if one open the scanner top often. It was not obvious in the beginning before I took apart the printer, as the wire is actually somehow hidden inside the hinge. In the pictures below, as I open up printer and took out the wire and it became obvious the wire is broken inside. There are 3 color wires running inside a bigger black jacket. Once I cut open the black jacket, the color wires are exposed and shown the damage. It took me quite some time to disassemble the printer, reconnect the broken wires via soldering and put them all back. It has worked flawlessly ever since.

[WalkingPenguin]

This most likely a design flaw of the printer, as this wire runs too close to the hinge. A minor assembly offset could result in mechanical damage of the wire.