dim faint green light on my charging cable, laptop won't turn on

i recently bought a new charger for my macbook. I plugged it in and it lit up bright green and started charging the computer which had a dead battery. I then shut off computer and removed battery to upgrade the ram, but the ram i purchased was the wrong fit, so i put back in the original ram. Then i put the battery back in and I plugged charger back in but it didn't light up, if you cover the light on the charger you can see it is an extremely dim faint green lit light. And the computer is not charging. Is it because I removed the ram or is it possible its the dc in board , which by the way seems to be pretty dirty/corroded