[Milsurplus] Strange Eimac 4-125 Tubes

[Jerry B.]

In going throught some boxes in the garage and came up with a sizable
quantity of NOS 4-125's.
I have no equipment to test them in. The best I could do is check the
filaments for continuity.
3 different Brands: Penta Labs, Lewis and Kaufman, and Eimac. The Penta Labs
and Lewis and Kaufmans tested OK for filament continuity. 2 of the 5 Eimacs
checked OK. However, the other 3 did not. The filament pins are supposed to
be pins 1 and 5. The other 3 dont have continuity between pins 1 and 5.
Instead there is continuity between pins (1 and 3) or (pins 5 and 3). Pin 3
is supposed to be the control grid.

Has anyone ever run across this problem?

These are Military Surplus. The Penta Labs and Lewis and Kaufman are marked
as 4D21 which is the Military number. The Eimacs are marked as 4-125.

73s
Jerry
N6AJ