Making Mixer Diagrams - by John Leigh / phil

The manuals for the earliest machines are ... suboptimal. They tend to show pictures of the units, but provide no details on which lugs the game wires were attached to, how the rivets connected to the wire lugs, or how the wipers were configured.

Over time, they added more text around the pictures which helped, but they finally started including something similar to the engineering blueprint for the units in the manual. Well, most units. Some of the units bally simply did not want the operators screwing with - the mixers, reflex unit and random units on late 6-card machines were left out of the manual. That didn't stop people from figuring them out, but to do so you needed to take the units apart and effectively draw the unit diagram yourself.

The process more-or-less goes like this:

  1. disassemble the unit so you can see/take pictures of the rivet side and wiring side of the contact plate
  2. take pictures of the wiper assembly
  3. for the contact plates, visually or with a meter determine which wire lug each rivet connects to. Visually is easiest.
  4. identify the wire id of each wire connected to a lug using the schematic and when necessary a meter and some wire isolation tricks
  5. make the diagram ... or get me to do it

This how-to will cover getting the data for all the mixers in a Bally Miami Beach. Guess we'll do it one mixer at a time. Obviously, to get the pictures needed, you have to take the mixer shaft apart. That's covered in the overhaul section on the site. Yeah, I know it's kinda like writing a how-to on replacing a clutch in your car and step 1 is "remove engine", but if they can do it, so can I.

Take Highest Possible Resolution Pictures of Mixer 1
mixer 1 - rivet side
mixer 1 - rivet side

The rivet side is useful for a few things:

  1. see when rivets or rings of rivets are missing
  2. see which lugs are used on the contact plate
  3. see the wire colors on the lugs .. so obviously get a good bit of wire in the picture. It helps to have the harness in the pic, as the wire colors are sometimes easier to see in the harness
  4. see if individual rivets or a solid ring in used
mixer 1 - wiring side
mixer 1 - wiring side

This is the critical part. You have a couple options when a bunch of wires are crossing and it's hard to see what's underneath:

  1. move the wires and take another picture
  2. wait until a preliminary diagram is drawn and then verify my guess - assuming I'm drawing the diagram

I usually bend the wires "up" or reposition them if I'm taking pictures. Otherwise, I'm usually writing on a blank diagram so move the wires enough to see under the piles.

Notice the cut wire between the end lug and the adjacent one?

mixer 1 - rotor
mixer 1 rotor

The non-wiper side of the rotor almost always looks like the above and isn't really needed. Rarely, though, something odd is going on and the picture makes things clear.

mixer 1 - rotor wipers
mixer 1 - rotor wipers

The wiper side shows the wiper configuration and how they are wired together. It's essential.

Use the Ask Me Form To Contact Me, Then Email the Pictures
reflex unit
My Guess On the Diagram

I'll use your pictures and the schematic to guess at the wire colors on the lugs and the wiring on the contact plate. I'll email you back the diagram and any questions / things to verify.

In this case, all I needed was a check of what was under the area of densest wiring, and a quick visual by John confirmed my guess was right. Note, however, I'm assuming the unused solder lug should be jumpered to the adjacent lug. It certainly was at one time - you can see the cut wire. Whether Bally made a change or an operator cut the wire needs more machines to check. A picture I had of another Miami Beach showed the lug jumper intact, so that's how I made the diagram.

Mixer 2
mixer 2 - rivet side
mixer 2 - rivet side
mixer 2 - wiring side
mixer 2 - wiring side
mixer 2 - rotor
mixer 2 rotor - bizarre!
mixer 2 - rotor wipers
mixer 2 - rotor wipers
mixer 2 - extra connection hack
mixer 2 - rotor contact ring wiper

Mixer 2 has a solid wiper contact ring on the rotor! Apparently they ran out of space and needed to get another wire connected to a wiper finger on the rotor, so they kludged a way to do it. Afaik, this is unique to Miami Beach.

Otherwise, just the same process as mixer 1.

Mixer 3
mixer 3 - rivet side
mixer 3 - rivet side
mixer 3 - wiring side
mixer 3 - wiring side
mixer 3 - rotor wipers
mixer 3 - rotor wipers

Nothing different here. Won't even bother to post the picture of the non-wiper side of the rotor.

Mixer 4
mixer 4 - rivet side
mixer 4 - rivet side

Here we have the first major stumble....not enough wire in the picture to see what color wire is on the end lug. Process of elimination can be used, but there's some questionable other wires.

mixer 4 - wiring side
mixer 4 - wiring side
mixer 4 - rotor wipers
mixer 4 - rotor wipers

In any case, I took a shot at it and sent John back a preliminary diagram.

Mixer 4 Verify
mixer 4 - preliminary
mixer 4 - preliminary

I said this about the diagram:

  1. not sure what the tan spaghetti is doing around the 7 lug ... can you please check the connections on the diagram or move the wires some and take another pic
  2. one of the wires connected to the disk is solid blue ... huh. I took a guess on some of the wires:
    • 63-4
    • 65-3
    • 20-2
    • 90-4

John confirmed with a magnifying glass and pushing wires around that all the rivet to lug wiring was correct. That just left checking what wires were on the lugs, and for that you need to look at the schematic.

Mixer 4 Isolating and Checking Lug Wires
mixer 4 schematic
mixer 4 - schematic

One nice thing - all connections to mixer 4 were in one place on the schematic. First test was to:

  1. referring to the selection feature unit diagram in the manual, find which lug wire is 20-2 and put a meter probe on it.
  2. look at the diagram to see at what step(s) wire 20-2 is not connected to wire 91-5 and step the unit to that position. Alternatively, put paper under all the wiper fingers on the unit to disconnect them from the rivets.
  3. manually trip the Green 3-L scores 5-L trip relay

Wire 20-2 should now only connect between the wire lug on the selection feature unit and a lug on mixer 4. The other possible connections to wire 91-5 have been broken, so the wire is now isolated. With the meter set for measuring resistance, use the other meter probe on the lugs on mixer 4 to find which wire is 20-2 (it will have close to zero resistance) Turned out it was lug 9 and my guess was wrong.

Using similar logic to isolate wires, the remaining lug wires were identified. The typical techniques for isolating wires are:

  1. put stepper units at certain steps or put paper under the wiper fingers
  2. trip or reset trip relays to open/close switches
  3. put paper between closed switch contacts
  4. when mixers are installed, turn mixer rotors backwards to make/break circuits
  5. distinguish between almost zero ohms and greater than a few ohms. You can't use a continuity tester for this, you need a reasonably sensitive ohmeter/multimeter. A reading of almost zero ohms means a closed circuit path that doesn't go through a low resistance device like a coil or lamp, while greater than a few ohms usually means you're going a roundabout way through a coil and other circuits. Roundabout can still be a valid approach to verify a wire in many cases, but you need to be careful. It's usually easier to figure out a way to create an almost zero ohm path and use that.
  6. very rarely, you may need to unsolder a wire

John gave me the results of the ohmmeter testing and I fixed the preliminary diagram for mixer 4 and posted it on the web site.