What is this?

[akroper]

Not fishing related (as far as I know) but I'm hoping the Ohana hive mind can help.  I'm clearing out my late brother-in-law's garage and found this under a bench.  It is a home made wooden case about 12x10x5 inches.  The front has two rows of ten small lights and one larger round red light.  The left side and the bottom are solid, there is a 3/8 inch hole centered in the right side, a plastic strap on top, and a toggle switch centered on the back.  The case is put together with screws, so it isn't meant to be opened very often.
Inside is a maze of wires, capacitors, and I believe diodes and/or resistors.  Whatever this is, it is powered by a 90V (yes, 90V, not a typo) Eveready battery about the size of a deck of cards.  Battery No.490 NEDA 204. The toggle switch is inline between the battery and the rest of the innards.  The battery is dead.  I'm going to build a pack of 10 9V transistor batteries and see if I can burn the house down.
Mike liked to fool around with old portable vacuum tube radios from the 30's-40's.  I also found about 250 old vacuum tubes and a tester.  I'm guessing this thing is related to that, but what is it for?   

[JasonGotaProblem]

It's a machine that divides by zero. Don't turn it on you'll kill us all.

Just kidding I have no idea.