If the printer starts sprinting but no ink is coming out on the paper or film then it means that there probably is a short somewhere either on the mainboard or the print-head or the FFC data cables connecting the print head to the main board. In this case because the chances of isolating the shorts are too many, we would first start by checking the F1 fuse located at the back of the main board of the printer (L1800). In order to access the mainboard, you would need to power the printer off disconnect the mainboard from the printer and from the power board and then check the F1 fuse. If you are checking the L1800 then the fuse F1 is located at the back. If you are checking the fuse for the 1390 the F1 fuse is located in the front. Please refer to the following pictures showing the F1 fuse on the L 1800 model. It is recommended to change the main board, the FFC data cables for the printhead, and the printhead its self all in one go. 