I'm very new to practical electronics, where I've only studied the fundamentals (physics degree).

My manager has asked me to decipher the circuit diagrams in fig 2.4 of the pico 1000 small terminal manual, however I'm stuck.

I can't see how some of the R values have been determined.

For instance if you turn the page clockwise, the top left diagram appears to have resistors in parallel e.g R1 with R65 and R2 with R66. I can't work out where the values 65 and 66 come from.

Are these just different positions on the board or do they have something to do with R33 ?

If someone could explain exactly where these values spring from, it would be really appreciated.