Seems strange but my MP620 which I picked-up second-hand from a friend only worked for a couple of weeks before dying with the error: U052, incorrect printhead installed. I have refiled the cartridges with Hobbicolors ink. The coincidence is that my previous printer, an MP610, also died with a faulty printhead error. The only conomality between the two is that I used the same Hobbicolors inks to refill both, is it possible that these inks are causing the failed print heads?