How do I get to the inside of my hp All IN one printer, Model L7780 to connect the multi-wire planar cable from the control panel to the back of the printer.

If you have the old cable, you put them in the same place. If not, evenly spaced. They are ferrite magnets and are there to stop interference.

No one has documented this job yet.

https://www.google.com/search?q=HP+L7780+replacing+the+scanner+and+control+panel+ribbon+cables

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To obtain a wiring schematic or service repair manual for the HP Officejet Pro L7780 Printer, I recommend reaching out to HP directly. You can visit the HP Support website and navigate to the product support page for the L7780 printer model. There, you should be able to find relevant documentation, including service manuals or wiring schematics, that can assist you with your specific needs. HP's official support channels are the most reliable sources for obtaining accurate and up-to-date information for their products.

These videos might help

Open it up dum smuch

Partial reset the printer

• Remove the power cable from back side of the printer while its ON.
• Press and hold "#" and "3" button, while holding them both insert the power cable and release the button after 10 seconds.
• If printer turns OFF, press power button to turn it ON.

check cable connection, check at contol panel printer and fax, select the print that online, may you chose print that offline
i hope this helpfull, please rate very helpfull or helpfull if you think this helpfull
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exactly what kind of trouble , it can be related to any internet security or antivirus installed in ur HP laptop which is blocking IP of the printer to connect to ur Laptop and print . pls go to controll panel of ur Windows Os in HP laptop and uninstall the Internet security from HP laptop

in this model there is a problem with wifi connection, hp has just released its patch, connect the printer with usb cable and then donwload the patch from hp.com/support and then run the patch, it will find the printer and it will update the firmwar of printer, and i asure u that then it will start working fine,i have resolve this problem alot, i am from hp itself. :)

The L7780 usually has a duplexer which has a rear access panel on it but this is NOT the panel that the printer detects as open.

In the L7780 anything that is connected/slotted into the rear slot/hole is considered to be the rear access panel. This means the duplexer (which is standard on the L7780) is seen as the "rear access panel".

Stand looking at the back of the printer
Inside the slot on the right side you will see a green circuit board with four metal contacts on it. Check that these are not soiled or damaged in any way. Clean if necessary.

On the right side of the dupler you will see only TWO metal pins that spring out and should make contact with two of the contact points. It's possible that these are damaged and/or broken. You may need to free, re-bend, etc... these CAREFULLY so that they stick out properly. Ultimately the goal is to ensure that the metal pins touch the appropriate contacts on the circuit board.

If all else fails, check your warranty and contact HP to see if they can provide a replacement duplexer. If the circuit board itself (in the printer) is damaged though you may need to return the printer itself.

Hope that helps.

HP has a fix for the Internet Explorer 7 issue on it's download page. You can also install the full feature software for a newer model, I used the OfficeJet L7780 and I now have additional features plus it works in VISTA. Just be sure to select "WIRED/WIRELESS" when asked how to connect and select "CONNECT LATER" when prompted that the printer could not be found. Works great.