I'm looking for the shoe circuit board for a Nikon fit Sigma EF500 DG Super (the one from an ST doesn't fit). I have a spare flash that's been in the wars and have managed to track down all the replacement bits except this. If you happen to have a flash that's shuffled off this mortal coil, I'm sure I can offer you something for it. Or if anyone knows a dealer who would entertain trying to get Sigma UK to part with the missing bit let me know.... They want me to send the flash to them for service at about 2/3 of the price of a new unit.