Note: 1.In print entered please turn off the power of the printer, or it will cause the mainboard chip burned. After loading the print head, please don't install ribbon overhead 10 pieces of A4 document, so that make the new needle have a running-in process, and then put the ribbon. I hope you can be careful operation 2.If the original print head was broken and especially leaked ink, the mainboard has burned possibly , so please troubleshoot the problem of the mainboard before replacing the print head. In addition, the F1,F2 fuze wire of mainboard can only be replaced by the original fuze that has same current value and same model.if replacing fuze that is biger current value and different model, Both printhead and mainboard are possible to be broken 3.Print head requires lots of attention, It is easy to cause man-made damage if a non-professionals replace printhead blindly. There is a regulation that printhead is not warranty, and it is delicate and expensive, please do not make commissioning on the machine, and please treat it with caution 4.If you are not familiar with the machine, it is recommended that you had better send the print head to a repair station or find professionals to replace the nozzle, so as to avoid unnecessary losses and unnecessary troubleFeature Adaptable ModelsFor 3520 3540 WF3520 WF7010 WF40 WF600 WF7520 F190020 Series PrintersYou'll Receive 1Pcs Printhead For 3520 3540 WF3520 WF7010 WF40 WF600 WF7520 F190020