Touchscreen not working after screen replacement

Looking for some help diagnosing a problem with a touchscreen display. I've been working on this one for months now and I'm ready to give up.

I have an HP Envy 360 laptop, model number 13m-ag0002dx. Components appear to be cross compatible across some -agX models. Touchscreen was working until I replaced the screen. The new screen doesnt register the touchscreen at all. The old screen no longer registers touch controls either. I've now tried it out on 2 OEM screens and one aftermarket screen with no positive results.

The driver in question is ELAN EzTouchFilter. Power state of the device is shown as D0 as described here: https://h30434.www3.hp.com/t5/Notebook-V...
I have not been able to change the power state of the device. Touch is not responding in BIOS either. The laptop seems unable to find the physical device at all as far as I can tell.

My current list of likely suspects are:

  1. Windows/driver issue. Purely software and best case scenario. I reinstalled windows before replacing the screen and did not check to see if the digitiser still worked at the time.
  2. LCD cable torn/broken just enough to disable signals to the digitiser. No physical sign of damage present on the cables. There are 2 sets of ribbon cables that plug into the digitiser board, 1 from camera and 1 from LCD. Could be either carrying the signal but I would guess its the LCD cable.
  3. Incompatible screen/digitiser board but this would not explain why the original screen no longer responds.

Any help or advice would be highly appreciated.

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Hi @shahramm ,

What is the motherboard's board number, (printed on motherboard)?

You may need the schematics to find out what has happened.

Search online for "(insert board number) schematics" to hopefully find them

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Hi jayeff.

The board number, as far as I can tell, is L26110-601. I wasn't able to find any schematics online.

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Hi @shahramm

That's the HP part number, not the board number per se

Try looking for another number on the board maybe Compal or another brand name or starting with LA etc

HP doesn't make boards. Not many "laptop" manufacturers do, as they're made by specialist board makers to order from the laptop manufacturers.

Post some images of the board maybe it can be recognized that way Adding images to an existing question

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Hi Jayeff,

I've been trying to convince myself to open the laptop up and take another shot at it but after countless attempts I think I'm just done with it. I'm disappointed that the touchscreen doesnt work but otherwise the device is fully functional.

I am curious though, what would have been the next step after finding the schematics? How would you go about diagnosing the hardware?

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@shahramm

The schematics would show which wires the touch controls were connected to in the video cable, so that you could check for continuity from end to end in the cable or at least check if you can "see" the controller in the display assembly when connected to the wires at the connector

Nowadays a lot of the touch controllers are in the display panel and not on the motherboard so only a couple of wires are used in the cable i.e. two data wires.

Since you have replaced the display with OEM then as you say it's either in the cable or the motherboard.

The schematics would show where the wires from cable connector went to but I'm thinking that it would be direct to the motherboard's I/O controller hub (aka Fusion controller hub with AMD) i.e. Southbridge chipset.

Have you checked in BIOS for any settings that may enable/disable any input or USB function etc.?

Also I don't know the model but is there an option to disable the touchscreen with a function key? If there is have you checked if that does anything?

Have found some Envy x360 board schematics and they all seem to be Quanta DAO series but none had a touch screen option so that I could check

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