Fails to power on after closing the display

[CO-ASE]

Need the part numbers for the display cables and how to replace them.

Computer would not boot when pressing the power button, after a lot of testing it was traced down to if you close the display when plugged in or on battery the computer would not turn back on.  When the screen gets about 2 1/2 inches from closing it causes the display and the power light goes out.  The computer is dead and will not turn back on even holding the power button until the cows come home.

The only way to get the computer to turn back on is to remove all power to the motherboard, battery/AC and then hold the power button for ~3 seconds.  With the display open you can reapply power and then press the power button, the computer works normally unless you close the screen when power applied to the motherboard (doesn't matter if you have turned off the computer or still running the OS) and then you have to start all over.

I believe it is the cables but I can't find how to replace them or the part numbers so if someone could point me in the right direction I would appreciate the help.

[CO-ASE]

It is not the video cable, if you triger the screen closed switch this is what causes the issue.

Question:  What is the part number to replace the board that holds the screen closed switch?

[CO-ASE]

Does anyone have the Service Manual so I can get the part number and verify that I can replace the bad component?

My two options are:

1. Replace the power board with a working one – need part #
2. Remove the magnet from the display but that is a last resort as I could damage the touch screen

HP I have been in the industry for over 25 years and recommend your product for work and personal but I can't believe you can't give me the tools to fix this laptop.

[CO-ASE]

HP Parts was able to give me access to Service Manual 15t-as100 if you are not safe you could damage your computer beyond repair so if you open it up you need to read the service manual to protect from creating more damage.

Looks like the power switch is on the dual USB board, will verify this and will update the post but this could be a fix for less than $15.  I wan't to thank HP Parts working with me to get the service manual.

[CO-ASE]

Looks like the USB board has the power switch and desplay closed switch.  Have ordered the replacement part and should have it next week.  Should be about a 20 minutes minute fix and less than $15 in parts.

USB board (includes cables and 2 USB ports)   857794-001

NOTE: The USB board cables are also available using spare part numbers 858701-001 and 857802-001. 857794-001

[CO-ASE · Accepted solution]

Problem solved:  The cause of the issue was a bad USB board part #857794-001

Symptom:  Computer will not turn on.

Diagnoses:  Removed back cover to unplug battery and held the power button down for ~3 seconds to discharge the board, applied power A/C or battery and the computer would then power on.  It is critical not to close the screen after applying power as the USB board holds the logic to know when the screen is closed.

Cause:  There is always power to the power button and switch to detect if the screen is closed, this circuit failed and once the display was closed while power was applied to the motherboard it went into a failed state and would not turn on until reset by removing all power and holding the power button down.

I hope someone else might be able to fix their laptop that has failed in this manner after reading this post.  Cost of the part on eBay was $13.95 delivered to the door.