Repairing an old NES

Spotting a dirt cheap CRT television in a second hand shop in Trelleborg last weekend set in motion a chain of events that led to a Nintendo and a copy of Super Mario Bros arriving in the mail. Only thing is, none of it bloody worked. I got the old flashing red light when turning it on, and once blowing in the cartridge didn’t sort it I was out of ideas. Fortunately I found a very helpful YouTube…