Birketts in Lincoln is an Aladdin's cave of weird and wonderful old electronics. The last time I was there I picked up this lovely fragment of board with two seven-segment displays. If nothing else I just wanted to see what colour the LEDs were and maybe harvest the 2-digit display. I guess it's from some kind of stereo equipment, although a quick image search doesn't turn up anything with a 2-digit display like this. As you can see, someone has reverse-engineered it, added and labelled some wires and has also bodged a transistor into the data line. They've written 'Data is true logic' on the board. I don't know whether that means that the driver chips' serial inputs require true logic and the transistor ensures this, or that you should make sure that your data signal is logic level. Either way, this arragment works when I hook it up to my RC2014 which works at TTL levels. I'm curious about whether that transistor allows a 3.3V input. I don't t...