Take a look at the MVS manual scans on Briggs site <a href="http://www.hardmvs.com" target="_blank">http://www.hardmvs.com</a>
It should be visible on the left back corner of the pcb sticking out from under the metal shell (assuming your looking at the pcb with the JAMMA harness in front) Theres a bank of 8 dips, the one you want is #7, second from the right.