I’ve been over my 1954 Spitfire with a fine toothed comb and can help.

Tilt relay is on the large relay bank on mine.

Knock off button removes credits....you could rack up a lot of credits on these machines and get them paid out. Hence the knock off button. There is a separate start button on the cabinet front.

Here are some drawings I did while working on Spitfire, they may be helpful.

The first is a bit of a startup sequence diagram. Many of the relays are latching so you need to keep in mind when reading the schematic that a relay may be tripped even if it is currently not energized.

SCAN0013 (resized).JPG

Next is a breakout of the connector to the toggle switch, flipper buttons, coin door, etc. This was extremely helpful, I recommend making one for your machine.

SCAN0014 (resized).JPG

Some pictures of Spitfire, may be useful.

Tilt and Game relays on the bank -- the bottom relay is tilt, the one beside it is the game relay

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Seven pin connector as diagrammed above

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Coin door. I made a connector so the replay button can be used to trigger a coin drop.

IMG_3420.JPG

Tilt -- this had been moved to the backbox on my game, I put it back.

IMG_3421.JPG

Plumb bob area

IMG_3422.JPG

Meter was missing on my machine, I bought a 50V one on ebay.

IMG_3423.JPG

Knock-off area

IMG_3424.JPG

Did you mean to attach a picture? Not sure where the yellow arrow is.

The wiring for the coin door and replay button is comprised of three wires:

'30' (yellow) - attached to a coin switch post and runs back to the plug
'13' (red-yellow) - attached to one blade of the replay button; it then jumps from the blade to the other post of the coin switch; originates at the plug
'56' (white-brown) - attached to the other blade of the replay button; goes to a switch on the take-off switch stack

You energize the path two ways:
13 -> coin switch -> 30 (drop a nickel)
13 -> replay button -> 56 -> 40 -> 51 -> non-zero replay step-up (credits on wheel) -> 30

To make it free play you wire the replay button like it is the coin switch: 13 -> replay button -> 30

If you don't have a play count meter you'll have a '68' wire (brown-black) to the adjustment plug not hooked to anything.

That wire goes to the meter. For me it is colour 34 (yellow-green). On your schematic it is wire colour 68 (brown-black).