It appears to be a transistor used as a diode?
Possibly a noise source??
I can't find any info from the numbers on the device, it could be an in-house ID from some equipment manufacturer, which was very common some years ago.
CR designator usually means diode.
But according to the pictures,it looks like a TO-252 IC,maybe try to search FAIRCHIL MC7805CD or FQD3P50 3P50,and check if it is a replacement part.