The 1675 has a ZIF socket 7 not unlike standard motherboards. While playing around with the mysterious DIP switches to find a 500 mhz setting, I stumbled on a 475 mhz configuration which seems to do the trick. There are many ways you can destroy the machine through a careless maneuver. Also, exercise extreme caution when taking a soldering iron to a multilayer circuit board. Get yourself a torx screwdriver set and a 5 mm mini-socket wrench before starting.
Sound works out of the box, with no configuration required.
You will have to recompile and reinstall the kernel after doing this, but that's all part of becoming a linux expert. Generally it is a good idea to leave your current LILO configuration intact and add the new kernel as an alternate boot option until you are sure it works. It's a type III card with the RJ45 jack built right in the card. Information below this line is old and quite possibly out of date. However, Tom Gilbert reports that Open Linux 2.3 only has 3.3.4, so you may still need to updgrade the Mach64 X server to 3.3.5 for it on work on the 1675.