I figured it out. The smell comes from the phenolic wafers that separate the contacts on all of the relays and the stepper contact board.

I have that same smell in my 1957 Bally ball bowler, and an even stronger aroma that's almost identical in my 1953 United puck bowler. It's the same as my 1948 United WISCONSIN pin.

I picked up a relay rack off of Ebay as a spare, put it in my office, and after the weekend in there, the whole office smelled like the other machines. That rack has 16 relays, and a ton of those phenolic spacers, so it's GOT to be the source.

I wish they made a candle with that scent...I'd keep it burning in the game room all the time.

It could be a mixture of the phenolic, the wood, and the wiring. It's not necessarily a phenolic smell, but a combination of unknowns. Whatever it is, it makes up the most unusual, and pleasant "early-days" smell that just seems right.

Kind if like sticking you head into the interior of a 1950 Ford that's been unrestored with mohair fabric...can't mistake the smell and it brings you back to the past (assuming you were around back in those days).

Yeah, it's strange. I have two bowlers in my garage, one from 1957 and the puck bowler for 1953. If I keep the overhead door closed over the weekend, the whole garage smells like those machines. And, if I open the alley up on either one, it radiates within a few hours. That smell won't disappear, and I've grown accustomed to it. Nice vintage and antique smell mixed together.

Bakelite is different, although it stinks when burned, just like phenolic.

Phenolic is light tan or brown, bakelite is black.

I stand corrected. Both materials have the same base odor.

Phenolic is used as an insulator for stepper contacts and also was used extensively for printed circuit material before the glass-epoxy material became the standard. It's also used on all leaf switches as insulation between leaves.

Bakelite was the material of choice for early automotive distributor caps and oven knobs among other items.