I had a working power supply, until I put my Dig Dug cab back together... according to the wiring guide I have everything right but I get no response and really bad humming from the transformer. I know AC power is getting through since the monitor ticks on but no boot of the game or anything like that... ideas? did I do something wrong?

I'm at a loss!
edit: It's officially called a Atari Transformer Color Vector Assembly