Anyone have experience adjusting the Voltage reading on these? My less expensive meters have a single pot for calibrating, but this one has three. Labeled on the circuit board as V1, V2, and V3. I'd be interested to find out what each of them does, but mainly, I need to know which adjusts the Voltage reading.
Update: Thanks for the answers everyone! To answer some questions, I have a voltage reference that I like to keep my meters synced with. This one is a little off, and it bugs me. beyond that, I'm simply curious. :)