@theflamethrower
The power button being part of the keyboard with only the one cable makes me wonder if there is a pair of wires in the ribbon cable in the keyboard that signals the motherboard's Input/Output chipset. (This chipset is not the one that connects the peripheral devices, rather the one that controls the functions of the motherboard e.g. power light, other lights etc).
With other laptops that have a separately wired (or hard wired to MB) Power button, usually it connects directly to the chip i.e. earth at Power button is used to signal IO chip to start (or to stop) the laptop.
Looking at the maintenance and service guide for the laptop it appears to have a wide keyboard cable i.e. lots of wires, so maybe one is an earth and one other is the wire from the PB. See if you can identify the two wires by placing your Ohmmeter between a wire and every other wire in the cable (do this for all wires) and press the PB on and off to see if they connect to it.
This is all guess work as without a schematic (I couldn't find one either) I don't know how it would signal the board to turn on.
Also just because the laptop is charging this doesn't mean that other parts of the motherboard are getting the power they need when the laptop is in the off position. The power button is not a power isolating button,it merely signals what needs to be done, so there must be some power on the board somewhere. Even if it is a Standby +3V, this may be good enough to power the IO chip so that when the power button is pressed the laptop can be fully turned on from the state that it is in.
Hopefully you're following my theory ;-)
Hi @theflamethrower ,
Just to add to my answer.
I’ve located a schematic for a HP Chromebook 11 G4 that may help.
(there is a problem viewing the schematic on ifixit at the moment. I have notified the admin so hopefully they’ll rectify it soon. In the interim there is an image below. Alternatively click on the link and try to view the document and then click on History > Download and download it to your PC and then view it there as it will open properly this way.)
NOTE: This MAY NOT BE THE SAME as for your board but hopefully may give an insight as to how things might work!
On p.26 in the KB (KBC) (keyboard controller?) box on the page, there is a wire from the keyboard cable on pin 25 designated Power_On_L which connects to main IC on p.27 on pin M2 and also is shown on p.16 & p.18 of the manual. Hopefully this doesn’t mean the Power On LED rather than the power button
On p.14 it gives the Power ON sequence.
Just reiterating that this may be nothing like your board as far as pinouts etc BUT it may give an idea of how it works and also hopefully manufacturers wouldn’t change things that much.
Desperate times call for desperate measures. ;-)
(click on image to enlarge)
3条评论
Hi @theflamethrower ,
What is the motherboard's board number?
On the 3rd image down that you posted there is a sticker shown with the HP part number 455.09701.0051 on it and printed next to it is the motherboard's board number MB-CT???AWF2AWRCR36W.
If you could post the entire number (careful not to rip the sticker further trying to find out) it may be possible to find the motherboard's schematics by searching for "(insert motherboard's board number) schematics"
Have you checked that the power button is working by checking if there is an earth on a contact all the time and then seeing if there is an earth on another button contact when the button is pressed which disappears when the button is released, just to prove that the button works?
由 jayeff 完成的
Hello @jayeff ,
The printed motherboard number is "MB-CT:PGAWF2AWRCR36W". I will take your advice and attempt to search for schematics for the motherboard. As for the buttons, they are not something I have tested yet, so thank you for your suggestion. I will update you when I have finished testing the buttons and/or found schematics for the board.
由 Aiden 完成的
@jayeff ,
An update: I myself cannot seem to find any schematics for this specific motherboard. Also, it appears that I cannot open the keyboard any further than detaching the mousepad from the keyboard and removing its ribbon cable, which has consistent continuity (seems fine). The keyboard seems to be stuck together by a bunch of plastic bits, those of which I cannot seem to get past. I will still try to test some things and will remain open to more help.
由 Aiden 完成的