The only other thing I can think of is along the lines of what
joemac said.
In the below image the two smaller fets at the far right of the image have a mica shim, but do they have a plastic insert on the front side where the screw goes? This is how I've seen it done on other PSU's but it's not obvious from the image that there are plastic inserts in the holes. I would hope there was or the mica shim would be pretty pointless???
http://www.nskjaer.dk/antec/cwdata/antec10.html
either way get everything true isolated with your nylon bolts etc and then see...........
{rant} Oh and on another related point when are these PSU's ever going to look like they are not designed by a committee, and assembled by crack smoking cyber monkeys???. They truly are horrid inside and I'm not singling out the Antec here. (however Antec do have an annoying habit of putting lots of additional PCBs inside rather than using one
)
The Enermax was a mess inside, an Antec 400 watt I had was hopeless with additional little PCB's randomly screwed all over the place, along with messy connecting wires running all over. Even an expensive 600 watt, (larger than ATX form factor sized), PC Power and cooling PSU was just as poor looking quality wise. If your next motherboard came as messily or shoddily assembled as all the PSU's I've seen most people would send it straight back. PSU design seems to be stuck in a time warp, and there really is no excuses now days...........{end of rant}
