hi ive had this before when resetting a pace pull the red jumper and leave for 20 seconds then replace it then make sure the feed is stright off the incomer ie no splitters or any thing then just leave it it may take a while but it should come on and update if your not pure n l then you may have to set net id and freq i had to leave one over night once but it did come on hope this helps
Try unplugging box hold down channel down button on box plug in keeping button pressed down this booted mine back up hope this helps.Been told this can cause damage but i have done it a good few times still works.
put some nail van remover on tooth brush.put on leg of atem chips onboth or one what every you have.use heat gun untile van gone.does not take long.make sure you keep the atem chip in place.you will need to re do your net id and pin when done.same fix 4 888.should work you have nothing to loose.good luck