I have a Raspberry Pi and a custom HDMI screen board stacked as shown in the photo here.
If I use a 'standard' HDMI lead then I have no problem. However, due to the form factor a lead does not suit my application so I created a HDMI connector PCB as shown below, and this does not work (the screen just remains backlit).
The first mistake I apparantly made was assuming point-to-point connections. I metered out a lead that worked and noticed that the GND connections are not through connections. I cut all these tracks, the problem persisted. Even though I have not been able to find any evidence for not having point to point connections on any pinout diagram
I then dissected a known working cable just to double check I hadn't missed anything obvious and couldn't see anything. So then I cut down this cable to make it so it could at least get me up and running in my application ... however, the cut-down version now does not work (blank screen).
The commonality between the two is that there is no shielding and/or twisted pairs ... I thought that this might have some impact on quality, but not cause it to not work!?
There are many 'PCB' adaptor boards online, so I am sure this is not just a case of wrong impedance/shielding ....
Any thoughts and suggestions would be very welcome.