[Boatanchors] Do Inductor values ever increase with age??

[F W Mooney]

I have an audio filter from a National RBL-6 (regenerative longwave =
receiver, vintage 1944) that's supposed to have an LPF cutoff freq of =
3.5 kHz, and instead, it's down around 1.5 kHz.  All components have =
been checked and/or replaced--everything measures okay now except the =
inductors.  All three inductors appear to have increased their value =
since 1944!

I know this happens with resistors, but I've never heard of it happening =
with inductors.  I measured the reactance of each inductor by putting =
12.6V AC across it and a variable resistor.  When the voltage is evenly =
split between the resistor and the inductor, the reactance of the =
inductor is equal to the resistance of the variable resistor.  =
Inductance is then calculated as R/376.8.

My 4.7 H inductors came in at 10.7 and 11.7 Henrys, and my 7.7 H =
inductor came in at 9.8 H.  These inductors are huge, wound on iron =
cores, and weigh about 2.5 lbs each.

Anyone ever heard of boatanchor inductors increasing their measured =
value over time? =20

- Fred M.  KA1DGL