HP 15 no touch after display replacement

Flannelman

Member
Dec 5, 2006
145
0
76
Hi All,
So my wife dropped a glass dish on the laptop with the screen closed and cracked the OEM screen. No accidental damage coverage so I ordered a replacement screen by laptop MOD # and it worked but no touch. It didn't even detect a touchscreen was installed. So I return it and ordered from a different retailer this time the exact same P/N as the OEM screen. Plugged it in and hooked it up before taping everything together. Now I have display(again) and it detects touch compatibility(making progress) but touching the screen doesn't register. I have messed with all the software side items drivers, oem tests, etc.. with no change. I know that I seated the plug well when I dropped the screen in unfortunately it's already in the shell with stretch tape. Is there some secret squirrel option that needs to be turned on or am I just looking at a reseat on the plug ? Maybe a display cable replacement? The odd part is it isn't working in the HP OEM diagnostic tests either outside of windows which pushes me towards it being a hardware issue.
 

Cy_kkm

Junior Member
Jan 2, 2022
13
13
36
54
100D.space
I have no idea how heavy the glass dish was and from what height it was dropped :), but breaking the glass screed of a closed notebook requires a lot of force. 'fraid something else could have cracked on the mobo. Copper traces are thin, and bending it with such a force may tear a hair-thin crack in them.

All touch panel connectors I have ever seen all have a very simple interface, based on the standard I²C bus. It has only 6 wires: GND and VDC to power it up, standard I²C SCL and SDA for CLock and DAta, RST input for panel controller reset (a panel can be put into sleep mode over I²C, and the RST line wakes it up), and finally INT that the panel asserts when it has touch data for the host to read. I have no idea how the host detects if touch panel is connected, but it seems to me that it should have at the least a brief chat with the controller IC inside the screen module over I²C, so that part is probably alive. The only thing that would prevent the touch panel from alerting the host of the touch then is a disconnected INT line. Cleaning and reseating the connector could help in this case. This assumes that the panel interface on the mobo is sane—if it's damaged, it can become quirky in unimaginably many ways.

What you can also try is bend the mobo a bit. A very short displacement, like 1mm, can help find the problematic place. Put a many-folded piece of paper somewhere so that it pushes on it one way or another. Sometimes it helps a cracked trace to reconnect. You can also try pressing on it with something non-conductive, like a plastic pen, and see if there is a spot that makes touches register. Then invent something to press on this spot permanently when the case is assembled. Not a long-term solution, but with luck can give it some more life.
 

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