No touchbar after keyboard and backlight replacement.

[Bob_1972]

Hi, I have a 2016 A1706 where the touchbar does not work. There is no Touchbar control in the keyboard preference pane. The history is that the Mac had a new keyboard, just the keyboard and not the entire topcase, however after re assembly the touchbar is not working. The touch ID does work. We took this apart again and checked every visually and nothing appears damaged. None of the flex cables are damaged and it appears ok when inspected under a Microscope. Any ideas ?

Thank you

 

[2informaticos]

Should be knocked off component, or broken trace; maybe bad contacts.

Remember to start your threads posting 820-xxxxx board code...

 

[Bob_1972]

Hi, there are no knocked off components or damaged traces. If I remove the board from the laptop and then connect all the connectors the laptop boots and the touchbar works. If I then screw the logicboard in it does not boot, it goes to around 5.16v and then the amp metre shuts down and cycles. So all I can think is that somehow the logicboard is shorting on the case somewhere. I can not find any pattern. If I connect everything up and screw everything together it does boot but without the touchbar working. It does have a new keyboard and I am wondering of this is causing the issue.

Any ideas or suggestions would be welcome.

 

[2informaticos]

Possibly internal damage, on the copper layers.

 

[Bob_1972]

I have the exact same issue on a second device. The touchbar is working but when everything is connected up it is dead. Everything else works fine. I did the usual SMC, NVRAM and macOS reload. I have checked the logicboard and flex cables under a microscope and they are not damaged. Any ideas? I have gone to the source of the keyboards to ask for their input, I am not expecting much but it seems too coincidental.

 

[2informaticos]

Keyboard backlight works now?

 

[Bob_1972]

The keyboard backlight always worked and still does on both Macs.

 

[Bob_1972]

Just incase anyone gets stuck on this same issue I have a solution.

I went back through the documentation I had made when dismantling the Macs, this includes details about screw layout and I also took loads of photos of the Mac at different stages as I took it apart. I wanted to see if I had got anything wrong when I put the Macs back together. I noticed that although I had the screws in the right place with the new keyboard it does not seem to let the screws lay flush so the heads stick up albeit very slightly. These are the screws that hold the fans in place. I am not sure why exactly because it is the Topcase that the screws interface with and I do not have the original keyboard for comparison. I have got around this by cutting small peices of insulating tape and doubling a piece on top of each screw head. Now the Touchbar comes on so the Logicboard must have been shorting on a screw head at the point of the Touchbar circuit or a component. Luckily it did not seem to cause any permanent damage.