On a modern Williams/Bally game with a hinged head, the heads weren't
intended to be removed. However, it's often necessary to remove the head
anyway, to fit through a narrow doorway or fit in a small car.
Use a sticky label to label EACH connector that is removed, near
the connector, using the jack number such as "J101". Fold the label
around a wire and stick it back onto itself, so that it stays on.
Include orientation (up/down or left/right) on the label, if it isn't obvious. Make a system
that works for you, and stick to it. For me, I always looped the
label around the leftmost wire in each connector, and for vertical
connectors, the topmost wire.
Keep a list of weird connectors written down, so that you don't forget
any. Examples include the replay knocker, the single connector near the
audio board, the grounding screw, and so on. Also keep a list of what
connectors on the boards are unused for your particular game, so you don't
get confused when you're reattaching things later.
Put straps, such as garbage bag twist-ties, around both of the big
hoses of wires coming through from the playfield, at the area where the
wires exit the hose, to help keep the wires bundled together and reinforce
the hose so it doesn't split further.
After removing all the wires, put removable Velcro straps (loosely)
around the rat's nest of wires from each hose, so that each hose's contents
are held together in a bunch. It might also be worthwhile to attach a long
piece of string to each hose, then tie the string to something anchored on
the outside of the cabinet, such as the backbox latch. This makes the hoses
much easier to fish out, when they inevitably fall down into the body of the
game during transport. Remove these straps when it's time to reattach the
wires, of course. I like Velcro straps because they're easily removable,
which is good for temporary holding like this. So that you don't lose your
straps, loop them around a wire in the backbox when done with them.
Avoid putting stress on the connectors! Don't depend on the connectors
to bear the weight of the wire hoses coming from the playfield. Those
Williams connectors are already fragile enough. Use large twist-ties, from
trash bags, to loop around the brackets where the original factory cable
ties were. Between the head and body, there should be a little plastic
mount with holes in it, near each hose. Thread the twist-tie through here,
and around the hose. Make it tight. It will grip through the ribs in the
hose, so it will hold the hose in place, and bear the weight.
As for the circular wiring guides in the backbox, only route the wires
through them that permanently stay in the backbox. For wires to the
playfield that you will be connecting/disconnecting, just let them dangle,
without using the wiring guides. Once you've removed all the wires going to
the playfield, clean up the wiring that's remaining in the backbox, so it
doesn't get confused with playfield wiring later. This will make it
visually easy to see which wires you'll need to remove and which wires will
be staying behind.
When reattaching each strand of connectors, work in order, from the
bottom (close to the hose) to the farthest away from the hose. This will
ensure you don't miss a connection.