If you have problems finding the F1 fuse on your EcoTank's mainboard, you are not alone. First of all, let me emphasize that the F fuse doesn't control if a mainboard powers up or not. If your mainboard is not powering up, it is more likely caused by blown transistors. Check out this video about how to fix the transistor/MOSFET.
The two transistors can be seen below, and the replacement can be found here (click).
If your F fuse is blown, the printer will print. But the output is blank. Of course, if your printhead is clogged, it will have the same symptom. Therefore, you need to troubleshoot the printhead and use a multimeter to test if the fuse is blown. For replacement, you can find them on Littlefuse.com. Pick any fuse with similar dimension and 1Amp tolerance.
Older models have the fuse marked as F1, so it's easy to find on the main board. For example:
Okay, here is where the fuse is. Hint: Epson doesn't call it F1 anymore. It is F201 or F301 now.