[TenTec] Triton IV lamps?

[brainbol@sunflower.com (BobR)]

The Triton IV 540 has three dial lamps
in the front panel, two are wired series
and the 3rd has a 150 ohm dropping resistor,
all appear the same.  The manual describes how
to the replace the ONE dial lamp yet schematic
shows the three.  Description says 6 volt @
50 mils for the "one" lamp.  There is no number
on my lamps. Dimensions: about .022" x .065" with
wire leads.  Anyone have a replacement number?
Tnx,
Bob/WB0AUQ