Answer to: My Brother Printer EMFC-J4510DW won't turn onDoesn't turn on after standby. This seems to be a common problem on many printers of this series, but the solutions presented here are just a workaround. You have to go and unplug your printer each time you want to use it. Quite silly for a WiFi printer... I've dug a bit deeper; the problem lies in a supercapacitor 5,5V 0,22F on the main pcb motherboard. It's unable to keep a charge and therefore the printer fails to come out of standby. You can get to the pcb by removing 9 screws, unplugging a few connectors and a bit of fiddling. Go in from the top, remove the scannerbed and work your way down. The supercap itself is a throughhole part that's easily replaceable with a standard soldering iron and costs around €2. Good luck fixing this chinese piece of $@$* and getting your money's worth out of it!!