A Huge Jump in the Learning Curve!

With the cabinet completed as far as reasonably possible, I turned my attention back to the internal mechanism. Here's how it looks right now:

Or perhaps more correctly, this is what it looked like just a few days ago. Regardless, despite the lack of turntable, amplifier, and tonearm assembly, everything visible here was powered-up so that I could check the operation of the Selector Unit (pin bank) and all of the Selection Buttons.

Now, I have the Installation & Service Manual, the Parts Manual, and a very legible copy of the electrical schematic, and while I thought I had installed everything correctly (LOL!), it didn't take too long for me to realize that I was only just beginning to learn how this thing really works!

First off, I double- and triple-checked everything that had anything to do with the controls and the Sequence of Operation. Switches, relays, wiring....everything I could think of. So when I powered-up the Power Supply with only the Magazine Motor installed and got nothing.... absolutely nothing, I thought, "Ok. I've simply missed something". So I grabbed the Manuals and re-checked everything. Again.

Still nothing.

But I wasn't getting voltages to the proper places, so I unbolted the Gripper Motor and started cycling the Gripper Mechanism, figuring I may have a Micro Switch that was out of adjustment.

Bingo! The unit took off!

I adjusted all of the switches (I'll do a separate write-up on that procedure, as well as make some videos), and when everything worked properly I started pushing buttons.

Long story short: No action when buttons #1 and #27 were selected. Everything else worked just fine, which told me that most likely the issues were electrical in nature, and specific to that individual  circuit.

Here's where my Learning Curve jumped-up! Looking at the wiring diagram I could never understand how, for example, Selections 1, 21, and 41 were on Pin #2 (pin on the wiring harness plug), Selections 2, 22 and 42 were on Pin #3 (etc). How could three different Selections come down the same wire?

So I had to sit down and figure out not only how the switches work, but how they integrate into the jukebox as a whole.

Here's a picture of the electrical connections on the #1 though #10 "Key Switch" (the Selection Buttons assembly):

And here's that same picture, but marked-up to show that there are 6 horizontal "levels" of contacts. In other words, each Selection Button has 6 sets, or "levels", of contacts, and I've highlighted the even-numbered levels simply in an effort to make this easier to visualize:

To paraphrase the Manual somewhat, the different Levels are responsible for the following:

* Level 1: Completes 25 VDC circuit in Accumulator (charges 300 MFD capacitor)

* Level 2: Dissipates capacitor charge into energizing Reset Coil, and which cancels 1 credit

* Level 3: In series with contacts on LH side of Impulse Switch (in Accumulator)

* Level 4: Divided into three sections (Selections 1-20, 21-40, and 41-50), each selection connected to the corresponding Clapper Coil.

* Level 5:  In series with contacts on RH side of Impulse Switch (in Accumulator)

* Level 6: Connected to individual Selector Coils in the Selector Unit

At first this can seem a little overwhelming, but when you break it down and use the wiring diagram, essentially what happens when you push a button is that voltage is sent to the Sector Coil for that particular selection (Level #6, above), but via wiring external to this switch, it may be sent to as many as two more coils as well! For example, when button #26 is pressed, not only does the Selector Coil for #26 have power (via Pin 7), but #6 and #46 also have power delivered to them.

So if three different Selector Coils are receiving voltage, how does the unit know which selection is the right one? Because these coils are not grounded (at least not yet), and without a complete path to ground, the coils won't energize. So how are they grounded, you ask? Answer: At the at the same time that a Selection is made, the Clapper Coil for that individual "group" of selections is energized, which completes the path to ground (Level #4, above)!

In other words, once a button is pressed, all three of the coils called-out above have power to them, but since only the Clapper Coil for the 21-40 "group" is energized, this action closes the "ground" circuit for the Selection Coil #26, the only coil that is actually energized!

On the wiring schematic this is shown here:

 Notice that when the White wire has power on it, Selector Coils #1, #21, and #41 will all have power available to them (a Level 6 action). However, the proper selection can't be made unit the corresponding Clapper Coil is pulled-in, which "grounds", and energizes, the correct Selector Coil (a Level 4 action).

Ok, so back to my issues with Selections #1 and #27.....

Since I could hear the Accumulator and Reset Coil energize when I made either selection, and since the "related" selections (in other words, #21 and #41, etc) worked just fine, I knew the problem had to be somewhere in the Selector Unit. To prove this I manually moved the Selector Lever for both selections at the same time I hit the selection button.....and they both worked.

Bad ground, possibly? I put jumper wires on the "ground" side of the Selector Coils as a test, and when I made the selections- Success! My suspicions were confirmed!

So what did I find? Well, #1 was easy enough to see, once I removed the Selector Unit:

Do you see that contact that is not lined-up with all of the others? Somehow..."someone"...(cough, cough!) bent the ground contact on the Clapper Coil! I'm not sure how this happened, but thankfully it was a simple fix!

#27 was a little harder to find, as I couldn't see anything obvious, and the circuit checked-out electrically. Or rather, it checked-out most of the time, as I finally stumbled across the problem. In the end I found that the coil wire was broken at the solder joint, but depending on the position of the wire, sometimes it made contact, and sometimes it didn't.

Looks good from this angle, right?

However.........

I'm pretty sure I know how this happened, as this wire is located right where I want to grab the Selector Unit when I pick it up, and no doubt one of my fingers got in there. Another simple fix.

And so with these repairs made, everything worked "hunky dory", right?

Wrong!

Now #6 didn't work! (Me: "What the (bleep)??? It worked just fine before....")

Going through Selections #1 though #10 with my Ohmmeter once again got me some really crazy results (47k ohms, 58 Ohms, 621 Ohms), on selections that previously were "ok", and where, in a perfect world, I should be seeing less than 1 Ohm!


The culprit turned out to be bad/broken wires in the #1 - #10 selection harness, as my readings would jump around as I moved the harness even just slightly. I cut-back the harness cover and considered locating and fixing the offenders, but when the problem got worse/more widespread, and I broke-off two wires at the plug, I said, "Screw it!", and I checked the harness on the parts unit.

That one checked "ok", so I ripped it out of that unit, and threw it in this circuit- while it was still dirty and grungy. Worked perfectly, even dirty! A thorough wash and dry, and- Voila! All of the selections work!