Well - I can see one voltage regulator - VR1 - but what it's for or such, who knows (well, you have the board, so you could find out). What's actually more interesting to me is U14 - that whole section around it appears to be the main power supply "nexus" if you will. Finding out what that IC is and what it supplies would be very useful/helpful. Also - measuring the voltage after those 0 ohm resistors/jumpers just southwest of U14 would also be interesting; it appears to be the main positive rail for the entire board. Likely, the positive "rail" is the plane on the top, and the negative/ground rail is the plane on the other side of the PCB (just guessing, though). Basically the fat light green areas are large "filled" traces meant to act as an RF reduction purpose. Likely, VR1 taps off of this. I would suspect that U14 outputs something lower than 12 volts, and VR1 takes that, and likely reduces it further. Maybe U14 outputs 5 volts, and VR1 takes it to 3.3 volts - or U14 outputs 3.3 volts and VR1 takes it to something even lower. Finding information on the other chips, datasheets and such - can help you figure this out more.