Epson 7800 problem/damaged head?

Hi all,

Bit of a long shot - but just wondering if anyone has experienced a similar issue with an epson 7800 (or like). I have performed the usual nozzle check and power clean, and even some manual cleaning following advice of several youtube videos (cleaning wiper blade/spit pad) but still no change. It does still print quite well but certain colours are affected and darker colours quite insipid/pale looking. Might be an inoperable print-head issue but I'm just exploring all options to avoid scrapping! Any advice appreciated! Thanks.
Graham
UK