This is for my vaio f series laptop which I bought in Europe 2 years ago (from what I can tell it is nearly identical to the one sold in the US)
A few months ago, my dc jack had broken (or at least i think so). It was very loose and there were only two awkward pins inside. I replaced that after a long time and it now works. However, when I try to turn my computer on (with and without the battery and ac adapter) nothing happens and only the green power button flashes after every 4-5 seconds. I tried holding the power button down to "decharge?" the laptop and tried then and the same problem persisted.