1. How to set the 1t/10t links correctly
Several people have had trouble understanding how the links for the TUNE pot (VR1) should be set when using either a 1 turn or 10 turn pot. The instructions in the NorCal 20 manual are not all that clear. The pictures below will clear up any questions anyone may have.
If you are using the standard 1 turn pot, as supplied with the kit, you need to make the links like this:
If you are using a 10 turn pot you need to make the links like this:
2. 10 Turn Pot Type
The PCB is laid out to accept many different manufacturer's 10 turn pot types. The 10 turn pots to use with the NorCal 20 rig are fairly standard 7/8" precision wirewound pots that are available from many manufacturers. Here are just a few possibilities:
534 series 10K part, see http://www.spectrol.com/533_534_535_537a.html
3540 series 10K part, see http://www.bourns.com/pdf/35401.pdf
7286 series 10K part, see http://www.bitechnologies.com/pdfs/7280.pdf
Mouser Electronics has most of these pots in their catalog.