When working with Linear Voltage Regulators it is important to take a good look at the datasheet for each model you are using. Never assume the pin placements are the same, even when the components look exactly the same.
Our device uses a few different regulators, all from Texas Instruments. A look at the diagrams for the TL780, LM237 and LM317 below reveals an easily overlooked pitfall. The pin placement for each model is completely different! Notice that the heatsinks for each of these packages also have a different assignment.
LM237_ADJ (-5V regulator):
LM317_ADJ (3.3V regulator):
TL780-5V & 12V
These regulators do have the same pin diagrams.
In our case, overlooking these details only resulted in some odd multimeter measurements, and a quick reference back to the datasheet revealed our error. However, we could have easily damaged a few components or worse. So please, take good note of all pin assignments before you breadboard.