HP Elitebook 8440p Won't Power On

[andymc71]

I have an Elitebook 8440p running Windows 7 that will no longer power on. Until recently, it was working just fine. Battery is past its prime, only lasts maybe 30 minutes, but I mostly run on AC anyway. I did have an issue a while back in which the AC adapter wasn't detected, so I did the whole procedure to remove the battery, hold power button down to drain residual charge, etc. and it worked fine. I thought perhaps this was the same issue, but doesn't appear to be.

I first attempted the above procedure a couple times, but had no luck. Then I tried reinstalling drivers for the battery, with no luck. After a few restarts, the battery was totally dead, so I was unable to contiue any troubleshooting that requires the computer to be on.

Now, with AC adapter connected, when I press the power button, I get 9 or 10 blinks on the power LED. This occurs with or without the battery installed.

AC adapter appears to be OK. I tried with 2 other AC adapters, same results.

Then I thought perhaps the DC jack was bad. I was bummed, as soldering a new DC jack is well outside my skillset. 

I thought I'd try a dock, as that would provide power separate from the DC jack. I got my hands on an appropriate dock, but still same results.

I do not have an alternate battery to try. I'm hesitant to spend money on one, as I still have no way to charge it.

It is possible I have a bad dock, but at some point, I can only get my hands on so many redundant parts to double- and triple-check things.

So, I'm stuck. If it's BIOS or driver related, I can't do anything without power.

Anyone have any suggestions? Thanks!