Hello

Epson C5790 printers suddenly stopped printing magenta. Black is coming from magenta nozzles. İt is not clogged printhead. Because magenta nozzles printing in black color perfectly.
İ did several clean cycles ink charges , ink ejects. Didnt make any change.
İ flushed with cleaners. Hot pure waters. Ultrasonic cleaners. İnk coming from nozzles without resistance. Didnt worked.
İ changed printhead with a good printing one. Didnt worked.
İ thinked maybe waste ink pad not vacuming ink and changed the ink system unit. Didnt worked.
Another opinion maybe ink pump not making enough pressure and changed all ink supply unit. Dint worked again.
İ dont understand whats wrong ? 4 of my machines giving the same error.
İs there any possibility that epson is locking machines after some counters?