Probook 650, won't power on, blinking charge light

[alexdwca]

I was not at the laptop in question when this started, but the laptop either suddenly turned off or would not turn on. power button unresponsive. charge light blinks a bright orange, occasionally alternates between steady orange and blinking green. the pattern repeats every 12 seconds. 

any information on what the charge light pattern means or troubleshooting to do when the machine won't turn on would be greatly appreciated. 

this forum describes the same issue but was closed by an HP rep before being answered: https://h30434.www3.hp.com/t5/Notebook-Boot-and-Lockup/ProBook-650-blinking-power-LED-no-boot/td-p/5...

[Huffer]

The symptoms you describe would generally mean a defective motherboard. Have you tried removing the battery and AC power and hold down the power button for like 20-30 seconds, then plug in AC power not the battery? Called a hard reset and its always worth a try although not often effective. There are at least 8 generations of the Probook 650 covering a pretty wide range of hardware options so it would help to have the exact product number of the laptop. 

https://www.hp.com/us-en/shop/tech-takes/how-to-find-hp-laptop-model-number

[alexdwca]

HP Probook 650 G5

ProdID: 7kw37ut#aba

i found similar instructions for a hard reset that went:

1) power off device

2) disconnect battery

3) unplug AC

4) hold power for 15+ seconds

5) reconnect battery

6) plug in AC

7) power on

following these steps, i hit power button, keyboard backlight came up briefly with a steady orange light, but then went right back to the blinking pattern without powering on.

my current plan: i disconnected the battery again, held the power button, reconnected the battery and plugged it back in. im gonna let it sit on the charger to see if that miraculously revives it or until i get a better plan. im not hopeful as its still giving me the blinking pattern but i have few options.

some other relevant details: this laptop was purchased at least 4 years ago and has been used by multiple different people. the most current user has not taken good physical care of the device (bends, cracks, and wear in the chassis that weren't present before). also, when i opened the laptop to get to the battery, a small amount of liquid was present. 

[Huffer]

I keep the battery out of the laptop while doing a hard reset. A very dead battery can prevent the unit from turning on.  Charging the battery is not going to make a difference. The presence of liquid makes it about 99% certain you are looking at a dead motherboard. 

[alexdwca]

Update:

The laptop was left as described previously. It was left upside down, with the bottom shell of the chassis removed for over 24 hours. I just replaced the bottom shell and tried turning on the laptop (battery was left in, charger plugged in). 

The laptop powered on as normal!... mostly. It did take slightly longer than usual, but nothing too out of the ordinary and so far have been able to use as normal. I'm copying all of the user's data to cloud storage immediately.

Once that's done, I don't assume we're out of the woods. Ill see what diagnostics I can run. And i'll try to see how well the laptop runs on and off the charger and for how long. 

And certainly will provide educational resources to the user about cloud storage and general computer care. 

@Huffer your prompt and detailed feedback was comforting and helpful.

[Huffer]

Pleased you got it working.