Checked my Manufacture notes, and antique
fixture notes. I have no history of this company, but do own one of these Fresnels... ah' I remember it now and also a
PAR 64 from the brand in collection. My Inkie version is a BA-15s version = single pole and the shell of the lamp is the
neutral. This is the pre-halogen 1962 concept of such a lamp.
Given mine was a BA-15s (
incandescent) and your's is a BA-15d (
halogen), not a huge problem... but is also, the lamp
socket could have been upgraded - these lamp sockets do fail. Your
fixture could have been safely rewired for the better and more efficient / modern lamp
socket like the
Altman Inkie was later done on. My notes say c.1962-1972 for the
fixture age of at least my
incandescent version... Could be that old, or after 1972 your version is origional lamp
socket is BA-15D.
BA15s = SC Bay, Single-Contact Bayonet Candelabra 5/8" (0.59") Dia. (
LCL at top of Alignment Pins)
Base Length 0.775". DIN #49720,
IEC #7004-11A,
ANSI #C81.61-1990sheet 1-20-1
BA15d = DC Bay, Double-Contact Bayonet Candelabra 5/8" (15.25mm) Dia. (0.59")
Base Length 0.775" (
LCL at top of Alignment Pins) DIN #49720,
IEC #7004-11A,
ANSI #C81.61-1990sheet 1-20-1,
Leviton Base #910-01, 910-200, 910-201 & 910-209
Basically the Ba-15s is single contact at the center of a glass
insulator and the shell is an
insulator to the outer wall of the bayonet locking mech. for a
neutral. The BA-15d is using two solder contacts with glass or other insulators and the bayonet shell is not in use other than mechanically locking the lamp to a focus.
One to another
fixture/lamp in upgraded they work the same unless you mis-match lamps into very similar sockets. Q of the day what happens if you put reverse lamps into either
socket.