I’ve just tried my Rainbow HAT and have found a problem with the LEDs. Only the rightmost one (labelled 0) ever lights up. There were no errors shown while installing the Python library and examples. Both SPI and I2C are enabled.
I’ve tried it out on two different Raspberry Pis and several Raspbian images, including a clean install, but no joy. I also tried cloning the GitHub repo, but there’s no difference. Surely it must be a hardware fault?