So every Friday I'm going to try and post a failure I've made this week. I cannot succeed without my failures, they're an important part of all my makes!
Today I was trying to get the Adafruit RGB Matrix Bonnet for Raspberry Pi working with my 32x64 RGB Matrix. The library doesn't seem to work at all with Python3 so it took me a while to figure that out and get Python2 working... but then the graphics looked weird. I went into the test file and tried out some different colours - only red worked fully, green was very faint and blue didn't work at all. A quick google mentioned a problem with power but my power supply is 5volts and 4amps and I was only trying to get "Hello World" to scroll across it...
I went back to the Adafruit page and the first image on the page solved all my problems! I was only connecting the data cable to the matrix, not the power cable! The big red chunky wire was missing from my setup! I had the wire next to me on the sofa... but hadn't connected it! D'oh!
Always look at the pictures as well as read the descriptions of setup guides