Atari used the sense on many (if not all) of their machines in the early 80's.
The sense is a feedback 5V from the PCB. With that, the power supply checks if it's still putting out enough Volts. If not, it will increase it a bit. Remember those were lineair power supplies that still used.
Sometimes, when contacts are very bad, the sense would indicate a very low voltage and thus the PSU upped the 5V too much causing burning parts. However, this is always a situation of a bad edge connector to the PCB edge.
Is there a reason not to use the original power supply ? If you're going to use something else I think you can just leave the sense disconnected.
