Epson 7900 "fix"
I had one of those defective carts. When inserted, the printer would not recognize it but returned an error message. Nothing I did helped, and I tried evey hint I found on the internet. Finally, I called the supplier who told me that Epson was having a problem with some carts. In the past, the suplier would overnight a replacement cart just on my word, but Epson took over and required them to direct all cart issues to Epson customer service. When I called customer service they gave me a Fed Ex return authorization # for a next day return, but it took another twelve days before I got my replacement cart back.
In the meantime, I'ves checked all my standby carts to see when they expire, because I know that had that happened, Epson would never have repaced the defective cart.