Flashing magenta print head on hp k850

[123cbboy123]

Hello I have a customer with hp k850 and always flashing the magenta printhead,also I change twice the head but nothing. Any ideas. About service manual, any link;

[Tec1]

haven't worked on that model, but have seen on large format if scanner belt is not in the right postion, it will say to replace various print heads???

[123cbboy123]

Dear I mean printhead.it's only printer. Although thank you very much

[Tec1]

yes i mean the belt that drives the print head assembly

[123cbboy123]

About service manual;

[austonrush]

This is just a printer. If the printhead didn't fix it and you have cleaned2 carriage and checked and reseated your contacts the customer should replace it.

[good]

Did you replace it with Generic or OEM magenta?

Replace it with an oem magenta.