I got a SCA390 adaptor for my Hasselblad to use Flash TTL but it misses the cable to connect the adaptor to the sync terminal on the lens. Now i thought i could build a cable myself. Given the socket on the SCA the cable seems to need a 2.5mm (3/32"?) jack plug. Does anybody know whether this is a two-conductor or three conductor plug and how it is connected to the pc-sync plug on the other side?

I tried a two-conductor plug, because flash sync would obviously need only two but the flash wouldn't fire. I checked for a faulty sync terminal on the lense, so its either a faulty cable, wrong wiring or wrong plug.