I have a dell 9300 laptop that required a power jack replacemernt. after replacind the jack, the laptop turns on {power light only) , for about 3 seconds, then shuts off. any suggestions??

Your battery is haywire, I have a similar Problem, I will be going to buy a new battery today for it, I will let you know how it went.

I assume that it wasn't always 3 seconds It has been going down slowly.

Fortunately you can repair your battery, you don't have to get a new one, but it's not easy.

bATTERY HAS BEEN DEAD FOR A LONG TIME .uSE AC UNTIL POWER JACK BECAME A MAJOR PROBLEM. I replaced the power jack, with great difficulty, and checked that I was getting power in from the jack. I didn't look to ckeck any lights {ie - used voltmeter).After reassemblying it and turning on, the powee light wouild go on for 2-3 seconds and shutoff. This happens conmsistently. How can i chec\k to see if power is getting to the hard drive?

I got a new battery and everything works fine,

You can check if the Hardrive spins up by opening up your Laptop and touch the hard drive and feel for vibration hear the spin up when you try top boot.

Usually the Hardrive has a seperate panel so you may not have to open everything up.

There doesn't appear to be any sound at all. From fans or vibration from hard drive. There must be a problem with the replacing of the power jack. I am able to get a voltage across both grnds to pos (approx 16.7v) however I I don't know where to check on the mobo to verify connection is good.