I have a 3 pin transistor looking device marked 6k(x). the last digit changes from unit to unit. The lone middle pin seems to be tied to the anode of two diodes, with the cathodes going to the other two pins. The strange thing is, there seems to be an internal 50 ohm resistor between those two pins. Any ideas here?

 

A close-up photo may help, plus any schematic you might be able to deduce. What is this circuit supposed to do?

Maybe you have a write-only memory cell?