It doesn't make much sense does it. I don't know anything about this printer. I don't know what cartridges cost but I'd be inclined to buy a new one to see if it works.
Your test does seem to rule out contacts. On my 2100P contacts were a huge problem - not just the contacts you can see but also the contacts on the other side of the contact block. Printers are a pain.
Eddie,


> Hi!
> I got an Epson DX7450 second hand. It came with no cartridges, so I bought a CIS system on Ebay with autoreset chips. However it does not recognize the black cartridge no mather what I do.
>
> They even sent me a spare chip for the cartridge but it did not help either. Any idea what should I do?
>
> It is not the contacts, because when I swap the black and yellow cartridge it shows that yellow cartridge is not recognized.