Newbie hades here.
My second-hand Presario F730 seems to have killed its power jack; the typical home handyman, I ordered a new power jack board, tore the machine apart (actually following directions from the repair manual, available online), and plugged it in. The new jack glows properly. Of the 3 LED's on the front, the one indicating charging blinks on and off. I can't tell whether the battery is charging.
When I try to start the machine, the only sound is one quiet click. The "on" light blinks for half a second, followed rapidly by a blink of the disk light. Period. End of story. No sounds of disks or fans, no lighting of the screen.
I've rechecked the connections, to the best of my ability - but I can't be absolutely certain I didn't mess one up. I've tried swapping the RAM in and out, trying on only one RAM (both units).
My best guess is that this amateur wrecked something in my messing around. Any advice, besides buying a new laptop?