I have one of these printers, and when it started to go wrong I contacted HP support. They were very helpful in the beginning, but were unable to resolve the problems so I retired the item.

Would mention that HP suggested using a different firmware from their range of printers, they never explained why, but it seemed to work.

In the end it was cheaper to get a replacement printer with new warranty, than trying to spend time in attempting a final repair. If you have new cartridges, then perhaps look at a similar printer that will accommodate the cartridges!.