I just got an old AT PSU from a guy. I want to test whether it works. I plugged a hard drive on it and plugged the PSU in the outlet, but it won't turn on. I know that ATX PSUs need to have two wires twisted up for them to power on, but I thought it wasn't needed for AT PSUs? Is there something I need to do for it to power on or should I declare it dead?
Picture of the PSU :