Any idea where could be the problem, electronic or contacts, cable or something similar? Looks like there is something wrong with comunication to those nozzles rather than faulty head especially because there is no improvement after new head was installed.
Thanks for any help and response.
Regards, Jaro
Completely agree about it more than likely not being the printhead. I had a similar pattern with a 6400. Here is my pattern.
What it ended up being was the main board. The way this was figured out was because first the carriage was replaced, and that didn't fix it, and so the other other thing to replace was the main board. Of course after each one, new heads needed to be installed. Thank god it was under warranty or else it would have been more to fix it than the value of the printer. In your case, since a new head didn't fix the problem, if it really is the carriage or main board, you will have to also now get new heads anyways cause the bad part, as we explained to me, will fry the other components down the chain. Since you have a 6100, I would say cut your losses and move on. You cannot go throwing parts at this, at your expense, and hope it fixes the problem. A new main board, new carriage, and new heads, plus labour, will be thousands and thousands of dollars. Simply not worth it for an old printer.
Edit: Perhaps you can try to make sure the contacts are good, and that the cable didn't come loose, but unless this really is the issue, I would say its dead.