first trip inside the machine

Let's open up our new old pinball machine!

Step #1 is get the key for the coin door.  Here is the inside of the coin door.

well hello in there

this is the coin acceptance mechanism

Let's take a closer look at that.   One thing that was pointed out to me was the tiny piece of metal that the validated coin hits on the way down.  If you tap down it gently with a pen, a credit will register.   There is no "Free Play" option on these older machines, so good to know in case you don't have quarters.

can you see that little metal lever, basically in the center of the photo?

And where does all the bounty go?  Straight in to the coin box:

oooo so rugged!

OK, so now it's time to open up the playfield.  See the opening in the top picture?  See that latch at the top of the opening?  That's the key to getting inside.  As best I can tell, this is pretty damn universal for about 50 years worth of pinball.  Pull that latch to the side and the front bar-rail comes off, and then you can slide the glass off.  This is all summarized in this youtube video.  That is a Simpsons Pinball Party.  There are 40 years separating these pins and it is the same action.
BE CAREFUL.  That glass is expensive, so place it somewhere where you won't bump it, preferably the end down on a carpet.  (feel free to Windex at this point, I guess)
Remove the balls.  This game only has one, so EASY.   Pull the plunger out, and lift the playfield up.

At the back there are rails for the playfield to slide on.

Slide it forward to the front resting area, and then lift it upwards against the backglass.

Glorious!

there's a LOT going on under the hood of any pinball machine.   The first thing that caught my eye were the 2 papers notes for coin slot adjustment.  When I got the machine, it was set for one coin  = 5 credits.  The little wires that attach to circles on the pins are chunky ol' jumpers to make your selection.  Just wiggle them out and put them at the selection you want.  On the left I have the bottom of 2 jumpers closed, so that is "1 coin 1 credit", which overrides the "2nd Chute Adjustment", which allows selection for 2, 3, 4, or 5 credits per play.  It should be noted that the coin door on my machine discusses Francs, so it allows operators to account for currency differences.  Let's not forget pinball had a dark period of being illegal in many major USA cities, so it was the international success that really drove it.

It's almost poetic.  Almost.

I love that things you are supposed to look at are so clearly labeled!  Just a bit closer to that we find this:

The three main fuses are placed in a wonderfully convenient location for easy access, and HEY, a play meter!

OK, 2 things about the play meter.  First, I don't expect that there has actually been 106,084 plays on this game.  I think in inspecting it alone we hit the credit button 100 times, each adding to the meter.
But hold on a sec, this meter goes to 999,999.  I think that says quite a lot about the confidence in manufacturing.   I'm not actually sure what other heavy-usage games from the era are reading, but to design a game that you expect to break half-a-million plays in a commercial setting?  That shows some confidence in engineering.
At $0.25/play, 100,00 plays is only $2500, so it seems reasonable, but to think some of these might have pushed a half million plays ($12,500) by the mid-80s?  That's impressive, even factoring in the maintennance.

Just to the left of this we have the awesomely simple tilt mechanism.

It's that vertical wire.  It's supposed to have a weight on the end, but I have that removed currently for a more push-and-shove game style.  If that wire hits the ring at the bottom, a circuit completes and it tilts.
What I was surprised by though is that upper-left pinball.  That thing is RUSTY, 37 years young, and if it rolls up it finishes a circuit and tilts.  I'm unsure as to why they'd need that.  If the machine was tilted up at the front, wouldn't the dangling tilt mechanism cover that scenario as well?  But well, there it is.

Having the machine up also gives quick access to the playfield light bulbs:

They are mostly uncramped, and easily accessible.

One final feature from the inside:

Thank you, # 74.  You approved a fine product.