Part of every trip home involves attacking the “to-do” list of things my mom can’t take care of by herself. She has several wonderful neighbors who do some more immediate things like plow and shovel her out when it snows (she mows their lawn in nicer weather on her riding mower), but other tasks can wait until one of the children visit. Wrangling the artificial tree from and back to the basement, lugging things to the attic, etc. are normal November/December/January chores.

But there were three bigger jobs. One neighbor has a very large generator that was put to use during the recent ice storm; our street only lost power briefly, but the houses behind us were on the wrong side of a fallen tree and were without power, and he supplied them with enough to run the heat and other basics. To facilitate hookup for the next power outage, he decided to shuffle some breakers in our house so he could backfeed through some outlets in the garage. So I helped a little with that.

The second job was to extend the recently-installed sump pump drain further away from the house; the original placement was on the high-elevation front side of the house, and only about 5′ away. The ground had become saturated and all of the water being dumped was just filtering back in to the basement. So I got to go down to the HO E DEPOT (the “M” was being replaced) and get some PVC pipe and run the drain line off to the side of the house, about 20′ away, and an area that will drain down the hill. There was snow on the ground, so I couldn’t do a proper job and bury the pipe, a task that will have to wait until better weather.

The last job was repairing the ancient pinball machine in the basement game room. It was a relic when we got it, about 35 years ago — relays and gears and a mechanical score display, which had gone out of vogue when digital displays and electronics came out. It hadn’t been looked at since my dad died, some 12 years ago, but hadn’t seen much use for a few years after that, until my nieces got old enough to want to play. By that time my mom had re-done some flooring upstairs and installed the old carpet in the game room, and it was some time later that we noticed that the key that opens the machine was missing, and was probably sitting on the floor, under the carpet and all of the junk laying on top. So, no access to the guts of the machine, until my mom had someone in to drill out the lock this past fall.

The Diamond Jack pinball machine has a wheel in the center, and when the ball passes through various gates, it depresses a lever and the wheel spins. There are 5 targets visible, corresponding to 5 cards in a deck, and each target has a contact behind it — if the ball hits the target with enough momentum, the target hits the contact and you get credit for that card, which becomes visible in the main display. Get A-10, or 9-6, or 5-2, and you get a free ball.

The problem was that hitting the target wasn’t completing the circuit, and the wheel ends up being about half of the scoring opportunities in the game. I thought it was an electrical problem, but once I opened the top I saw that all of the fuses were intact. The issue was mechanical — the set screw on the shaft that turns the wheel had come loose, and the contacts were out of alignment. So I realigned and tightened, eventually using some thread-lock when my first attempt came loose again. Voilà! The New Year’s Eve snowstorm thwarted the attempt to replace the burned-out bulbs, though.

One interesting thing amid all of the guts is the tilt mechanism. In order to discourage cheating by pushing, jostling or tilting the machine, there are internal components that react to such abuse. One is a pendulum; if the machine is tilted more than a few degrees in any direction the bar makes contact with the ring and completes a circuit; you lose the ball in play and one additional ball.

There’s another tilt device, which is comprised of a “U” shaped pair of flexible metal strips; one strip is fixed and the other has a mass at the end, and they are insulated from each other at the base. If the machine is rapidly shifted horizontally, as one might do to influence which slot the ball enters near the top, Newton’s laws can be seen at work. The system is only weakly coupled, so it’s not very sensitive to a high-frequency impulse, and the machine moves without exerting much of a force on the other strip. The strip remains approximately at rest, and the tips will meet and complete the “Tilt!” circuit.