This looks like a good starting point. Click on the "radio codes" button on the left.
http://www.spiral.com/nevada_county_scanner.php#
Granted it was 20+ years ago, but when I dispatched for GVPD we and NCSO didn't use the vast majority of the 10-codes on that list, but only the more common ones -
10-1 - Receiving Poorly
10-2 - Receiving Well
10-3 - Switch to Channel __ (or to "scramble" - simple voice inversion stuff back then)
10-4 - Understand
10-6 - Busy
10-7 - Out of service
10-8 - Available
10-9 - Repeat
10-12 - Are you clear to copy (warrant) information?
10-15 - In custody, off to jail
10-18 - Fueling patrol unit (GVPD anyway)
10-19 - At (or Go to) Station
10-20 - Location
10-21 - Phone
10-22 - Cancel
10-23 - Stand By
10-28 - Veh Registration
10-29 - Check for Wants
10-33 - Burglar Alarm
10-42 - Out at home
10-47 - Prepare to copy a call (GVPD)
10-48 - Go ahead with the call "
and 10-97, -98, -99 common Calif meanings
We also used the CHP's 11-79 thru 11-83 for traffic collisions, and 11-95 for "Making a traffic stop"
NCSO has a different unit numbering system from back then, but Nevada City PD and Grass Valley's seem to be the same. At the time GV didn't have any ranks above Sergeant ("37-xx") other than the Chief ("35"). They were just about to create a Lt position, which went to Sgt Johnson, but no Captain position existed for several more years.
For patrol officers, their unit numbers were semi-permanently assigned, based on seniority in the position: 38-1 being the most senior patrolman, 38-2 the next, then 38-3, 38-4 etc. Sergeants were the same, with 37-1 being the most senior Sgt, then 37-2, etc. Whenever someone left the department (which was real common at the time) everyone below them had their number moved up a notch.