I believe it is pins 3 & 4 on J21. J21 is on the left side on the front of the PCB about 1/2 way up.
It's a lot easier to instell the CPC upgrade kit. The CPC upgrade kit includes the port, cabling, and the voltage divider board so a 65 can be fully upgraded for $100. The kit number is 228697 and the part number is 806980 if you want to see the FSB installation instructions. It is a very easy mod.