Like I said, it will vary based on what you are measuring it with. I have a TMCC test board that I built to test the regulators, I have a light bulb across the smoke output to judge if the regulator is putting out voltage and also changing the output based on the smoke volume setting.
I mis-spoke! The brown wire is serial data, and the brown with black stripe is smoke unit voltage out. I also corrected my original post to make sure nobody gets fooled with my mistake.
If you're reading 7 VAC on the brown with black stripe, you're getting smoke voltage out of the regulator. The brown/black wire should go directly to the smoke unit, the track power should go through the smoke on/off switch. I'm curious why you don't read anything on the serial data line, I get 3.4 VDC reading, and a 2.3 VAC reading on that line to frame ground. If you read nothing on the brown wire, trace it out and make sure it's connected to serial data.
