06-19-2019 01:46 PM
Laptop powers on, black screen (although backlight activates), powers off after approx 10 seconds then powers back on and repeats.
Tried starting with windows key and "B" and windows key and "V" and no response
tried booting from a bios recovery usb but no joy.
Tried swapping dram sticks
Tried booting without SSD in place
Nothing makes any difference
I suspect a CPU or mainboard failure.
Any clues would be much appreciated.
06-22-2019 09:45 AM
Welcome to the HP Support Community!
Have you tried connected the computer to an external display and checked?
Meanwhile, I recommend you follow the steps in the below article and check if it helps.
Let me know how it goes and you have a great day!
If you wish to show appreciation for my efforts, mark my post as Accept as Solution. Your feedback counts!
I am an HP Employee
06-23-2019 06:08 AM
Thanks for replying.
Tried external monitor and tried all the steps in the article.
Tried updating the bios with a usb drive but the only updater that works is the oldest one, the rest just do nothing. Tried on 3 different PCs, including 2 HPs.
I still think it's a mainboard / CPU failure unless the bios chip has been totally fried.
Had no luck getting hold of a new bios chip either so looks like it's destined for the bin.
06-24-2019 05:14 AM