With a bit of trial and error I’ve managed to figure out the circuitry of the burner control panel. As I suspected the seven segment displays are common cathode and connected together in a matrix. Each cathode goes to one pin and each parallel group of segments goes to a pin.
There are four LEDs running up the left side of the display panel that I don’t fully understand. I know they must be hooked into the same matrix as the 7-segments but I can’t identify the pins they connect to.
The butons are also a little bit of a mystery. For some odd reason they have diodes connected to them. I suspect they’re being used as an OR gate so every button can trigger an interrupt on a microcontroller with a single interrupt pin. This means I can probably ignore it.
I’m probably getting a little ahead of myself but I’ve gone and designed a microcontroller PCB to sit behind the display panel. Hopefully I’ll be able to figure everything else faster once I can control the display through code.