Hello I am new to this forum, but I have stumbled across many helpful tips here and I was wondering about my seemingly dis functional Atari 400 computer. When I power it on, the power light comes on, the internal speaker makes two clicks (sometimes fast and sometimes more delayed), and displays a black screen. I am using the built in ref output connected to a tested ref modulator, connected to a tested TV. Everything seems like it should work, but all I get when I turn the power on is a black screen with no sign of input. I have tried to start the computer with a game cartridge already inside, but to no avail. I have also tried my basic cartridge, but still a black screen. I have seen on this forum that re-socketing the chips and cpu and rom/ram boards usually fixes this problem, but after I re-socketed every chip, but nothing changed. If there are any suggestions, I will be happy to try anything to save this old machine.