Latitude E6430 - Power Up Issues

Hello,

I have searched and read many posts in the community about power-up issued with the Latitude E6430.  There have only been two posts that resembled closely the problem I am having with mine with no resolution found.  One of the posts (June 2015) did not even receive a single response.  So, I am going to describe my issue here and see if anyone has any helpful ideas.

My E6430 has been working well for many years both using a Dell docking station and without the dock.  Within the last 2 months, it started not powering on consistently.  What happens:

     1) I press the power button on the laptop

     2) The hard drive LED comes on for about 1-2 seconds and then turns off.

     3) No other lights come on, blink, flash etc...

     4) I can hear that something is on (may be the HDD spinning, but not the fan)

     5) I then press the power button again and the fan comes on and with in 2 seconds, the system shuts down with a single beep

     6) During this time the screen never comes on.

When the problem started happening, it would take 1 - 3 additional attempts of following the above process for the laptop to power on. Once powered up, it worked well with no issues at all.  Once it was powered off after use, the same problem would occur with powering up.

As weeks have passed, it has taken more and more iterations of the above steps to get it to power up.  Sometimes 50 attempts.  Currently, I have had no success with powering it up and I am probably around 100 tries.  Seems like some sort of exponential degradation of something maybe.

I have tried:

     * with/without the docking station

     * with/without the battery

     * replaced the battery with a new one (OEM)

     * the "hold down certain key and power button for 30 seconds" thing to discharge the unit

The last time I was able to power it on, I ran a diagnostic and no problems were identified.

Any help would be greatly appreciated.

Thanks, Henry