I have a HP C4780 printer - does the 300XL cartridge work on this model

You can gain access to the service menu...refer to Cartridge Error Clear bypass procedure below (as guidance of how to get in):

For any severe cartridge error related message, on the HP C4600, C4700 or D110a printer models, I suggest you run the internal Tap 41 diagnostics test which will tell you the electrical health of the ink cartridge - in many cases the cartridge is internally electrically damaged and will need to be replaced. In addition, you can temporarily bypass an 'incompatible cartridge(s) or Missing/Not Detected error message by performing the Cartridge Error Bypass procedure...refer to two Youtube videos on how to do this:

HP Photosmart C4600 & C4700 Printers - Tap 41 Diagnostic Test: http://www.youtube.com/watch?v=ghxjLCn07Jo

HP Photosmart C4600 C4700 D110a Printers - HP 60 Cartridge Error Bypass: http://www.youtube.com/watch?v=rNVJmKPlLsg

Low Ink Warning and Other (i.e Incompatible Cartridge) Errors, HP 60 & HP 61 Ink Cartridges:

http://www.youtube.com/watch?v=5_suW3U6e08

Hello,

While the printer is ON, remove the cartridges and you may unplug the power cord from back of the printer.

Wait for 30 seconds.
Ensure the cartridges have ink in them ( atleast 25% ).
Plug in the power cord to the back of the printer. If printer does not power up, press the Power button on the printer to do so.

Initialization should complete.
If issue still persists, please call HP Tech Support for further assistance as the printer may require a service.

Yes it could be the problem. Try and get a different print cartridge and if it doesn't work you may just have to get a new printer.

The ink solidifies right behind the micro printing nozzles. The only way to attempt to rectify this is to dip the print face into some warm (not hot) water for a minute or two, and dry after wards. If the cartridge recovers, Yippee, if it doesn't, replace.
Common problem. Be thankful it isn't a Canon or Epson, which entails replacing a seriously expensive 'print head'.

For commercial reasons, HP have region locked their printers, so that you cannot buy a printer in the US and then take it to another region e.g. UK and buy the cartridges there, or buy cheap cartridges form another region. There is no way to re-program or unlock the region coding of the printer. You can either try to get your HP60 cartridges refilled or buy another printer.

Hi there!
You will see the cartridges once you open the front cover. Here's what you can do to check on your cartridges.
-Make sure the printer is on. -Open the front cover, the cartridge should automatically move towards the center. You will notice a pink and a black top cartridge and also instructions on how to replace cartridge on the cartridge door.
Hope this helps!

You have the wrong cartridges, that model uses the 300 or 300XL cartridge http://www.internet-ink.co.uk/hp-ink-cartridges-f4280/

http://www.amazon.co.uk/Original-300-Black-Ink-Cartridge/dp/B0019TUUJW/ref=dp_cp_ob_computers_title_0
http://www.amazon.co.uk/Original-300XL-Black-Cartridge-Capacity/dp/B0019TUUME/ref=dp_cp_ob_computers_title_1
regards

You may have a dud. Try using the cartridge in another printer of the same model. Otherwise return it to the store and have them test it or exchange it for another one.

Ok. As per your statement , the power cable is working properly. So , the problem is with your printer only. If you are using the original cartridges and still having the priblem , it is only the defualt printer. If you are having the extended warnty for (3) years , you are adviced to contact ' HP Authorised Service Partner'. they will replace your old printer with new one. Generally the HP company is giving 1 OR 2 years warranty for replacement.If have paid extra amount for extended warranty , your printer may have warranty up to (3) years. So, within the period of (3), the HP Authorised Service Center will replace your printer. They will give reciept for your old printer, and replace your prionter within a (15) days to (25) days with new one. If the printer is not having warranty or extended warranty , the printer is assumed to be as damaged. So, you have to purchage the new one. Be, cuacious the HP printers are not repairable. Please don't try to approach the local repairer.They will eat your money and also don't try to purchase very very very costly HP in cartridges. I think your problem may be solved.

Switch off the printer and switch on again,Unclip the cartridges one by one and clip back in again this sometimes cleans out the connector pins.This has happened to me.