Factory Reset for HP Photosmart C4780

[Sandra7621]

Step 1:  Make sure your computer is connected to the correct network. Confirm your settings for your home network; HP Printers - Find Your Wireless WEP, WPA, WPA2 Password (Mac)

Step 2:  Restore the Network Defaults on the printer so it's not holding onto any old information.

* To do this you should be able to touch on Setup [Scan] front of the printer then choose Network and then Restore Network Defaults

Step 3:  This would normally be to use a USB cable and your printer software to configure the printer back onto the network.  But since you have Mac OS X 10.10 Yosemite which uses the driver from Apple, there is no software package from HP to configure the wireless. 

So for you to get the printer back on the network you can follow the directions from this similar post, copied here for you below;

After you Restore Network Defaults, the radio will turn off (the blue LED will go out.) You may need to press the wireless button again to Enable Wireless (light should be flashing.)

Something gets fouled up somewhere between the Step 2 and Step 3 that you referenced. I select Restore Network Defaults and the light goes off. Then, I press the Wireless button again to Enable Wireless. The blue light blinks 2 or 3 times, and then it shines solid, no blinking. My computer then does not see the printer's own network signal, so there is no way to create an ad hoc connection.

I was able to print out the Wireless Network Test Report from the printer's electronic menu. In the "Diagnostics Summary" portion of that report, it says "FAIL" for the "Network Name (SSID) Found" test, and various other tests were not run, seemingly as a consequence of the failure on the SSID test. It also reports "not applicable" for IP Address in the "Configuration Summary" portion of the Wireless Network Test Report.

For what it's worth, I was also able to print out some other kind of report from the printer's electronic menu. That report indicates that the printer is seeing all the relevant networks, including mine, that are in the vicinity. Also, at this point, I am no longer seeing any sign that the printer has a memory of the previous network.

Where to go from here?