Adjustment #1: Magazine Motor Reversing Switch (w/video)

Reversing Switch Adjustment

The Reversing Switch is a 4-pole, double-throw, snap-acting switch which, A) reverses the polarity of the Magazine Motor armature (which changes motor rotation), and B) switches the Indexing and Cancel Solenoid circuits between the odd and even selections.

There are two adjustable Trip Brackets mounted to the front of the Record Magazine carousel (circled in yellow), and these brackets need to strike the Reversing Switch Trip Lever at the proper time so that the Magazine Motor reverses direction when safe to do so.

Note that there are two "tracks", or "grooves" on the front of the Record Magazine Carousel as well (an inner, and an outer), and a device called a Track Roller rides inside of these "tracks" (hard to highlight here, so please see video). At the end of each individual "track" there is a ramp that shifts the Track Roller from the Inner track to the Outer (and vice versa), along with a Cam Track Spring (a piece of sprung steel) that acts like a one way gate and prevents the Track Roller from going back to it's previous track

If you look close enough will see that Trip Brackets are located near these ramps. This is not by coincidence, as the Track Roller is mounted on a lever (the Gripper Connecting Rod) which "trips" the Reversing Switch Trip Lever!

Here is the Track Roller, currently riding in the Inner track:

And here is the Gripper Connecting Rod, as seen from the front (Gripper Actuator removed for clarity):

What happens is this: When the Track Roller is in the Inner track, the Magazine Motor rotates the Record Magazine in a CW direction, and when the Track Roller is in the Outer track, the Magazine Motor rotates the Record Magazine in a CCW direction.

Location of the Trip Brackets is critical, as they control the "timing" of when the Magazine Motor reverses. If it reverses direction before the Track Roller changes tracks, the mechanism could "bottom out" in the wrong track, resulting in bent and/or damaged equipment.

Here is a picture of one of the Trip Brackets that is just about to hit the Trip Lever (seen in the "up"position) as it rotates downward:

As seen in the video, I have obtained the best results by adjusting the Trip Brackets so that they hit the Trip Lever at the same time the Track Roller hits the piece of sprung steel at the end of each track. 

Link to video: https://youtu.be/YYkACJEBz1I

Fixing a "setback" by adjusting Setback.

Yesterday (Saturday) I was determined to find, and fix, the Gripper Arm-to-Record interference issue, and since I thought the issue lay somewhere in my rebuilt Magazine Assembly, I figured the simplest way to check this would be to swap them around.

 First, I pulled the Magazine out of the parts unit:

But in order to that, I had to remove the back of the unit, which meant I had to remove the top, which meant I had to remove the glass (you get the idea). Needless to say, it wasn't as simple as just yanking it out.

Then I had to pull-out the Magazine from the "good" unit:

And safely set it aside.

I then installed the "parts" Magazine into the "good" mechanism, with this result:

Yup! I still had the interference, even with a Magazine that hadn't been messed-with.

(Much grumbling ensued....)

Curious, I installed the "good" Magazine in the "parts" unit, and everything lined-up perfectly!

(More grumbling ensued....)

Then I happened to notice that I had a Reference Point I could use, something that I hadn't seen previously: There is a mounting boss, or ear, on the back of the Gripper Housing that lines-up almost perfectly with the end tab on the Reversing Levers on a "good" assembly (circled in yellow):

On the "bad" assembly they don't line-up:

Since I had this issue with both/either Record Magazines, it became obvious that the issue lay with the "setback", or "tilt", of the Gripper Housing. But since there were no shims or spacers shown in any of the pictures I took upon disassembly, I was skeptical that the factory had done this originally. Plus, I didn't see any marks (notes) near the mounting holes on the baseplate.

What I found, and what I think the factory did, was this: I have three Gripper Housings here, and all of them look the same on the bottom. However, the hole for the Outer Shaft is located in a slightly different position on each one, and what I think the factory did was they riveted the "Hole Block" (my term, picture below) to the Gripper Housing on a jig of some sort once they had all of the parts loosely assembled in the factory. I think this discrepancy between the different assemblies may have something to do with the interference issue I was experiencing, but there's nothing I can do about it.

Knowing I had to tilt the Housing back "just a smidge", as a test I grabbed two lock washers (from the mounting bolts of the spare unit) and used them as a shim between the Mounting Plate and Housing, on the two front bolts of the Housing.

Yesterday must have been my lucky day, as the results of this were absolutely perfect! Here's a couple shots showing the Gripper Arm-to-Record gaps after I had reinstalled the rebuilt Magazine:

 You can't argue with results like this!

Yet another setback.

A few days ago I really thought I had all of my bases covered, and that I was ready to install the mechanism into the cabinet.

But, sadly, once again I was wrong.

So what's the issue now? This:

That's a record sitting in the Magazine (as seen from the rear of the unit), and the record hits the Gripper Arm when the Magazine rotates! Yes, the Gripper is fully open, it is not damaged (it has the same dimensions as the other ones I have), the Magazine is in the proper fore and aft position (actually, it's not adjustable), the Gripper Housing itself is not damaged.....

From a previous post you may recall that I swapped Gripper Housings a few days ago, and I've been comparing critical dimensions between this unit and my spare unit/parts unit for a couple days. So far I've come up empty.

So, here's what I'm up against. On the old/parts unit the Gripper Arm seems to have equal gaps between the front and the rear of a record, as things should be.

* Front gap of (roughly) a 3mm on the "parts" unit:

* Rear gap of (roughly) 2mm on the "parts" unit:

Compare those numbers to these:

* Front gap of (roughly) 5-6mm on the restored unit:

* And rear gap (or lack of gap!) on the restored unit:

I really don't know where the problem originates, but all of the dimensions I've compared between the two units are identical. In fact, I've checked so many things that I'm starting to think I messed-up something when I reassembled the Record Magazine, so tomorrow I'm going to swap them out and see what happens.

(I was so close!)

One Sure Way to Shorten the Life of a Record!

Back when I was a kid and was playing around with that original 1452....Man, that thing used to "eat" records! I mean, you couldn't put anything "good" in there, at least not if you wanted it to stay in that condition, and with this unit I want to make sure that all of the records are treated properly!

So what do I mean when I say it used to "eat" records? In this case I'm not talking about the damage that occurs from too much VTF (Vertical Tracking Force), but rather the fact that the old unit wasn't set-up and adjusted properly. Specifically, I clearly recall that Gripper  Arm was not lined-up with the Record Magazine very well, and the records used to scrape along the side of the Record Trays (the "grooves" in the Magazine where the records are stored). As a kid I didn't know how to fix this (after all, I was only 5 years old or so!), but over the years I did manage to keep some of those damaged records as a reminder.

Here's an example of the damage that can occur:

And a close-up:

Not good!

Ok, keep this in the back of your mind for a minute.....

Recall that I had all of the brightwork either re-plated or re-chromed, and that chrome adds thickness (from several posts back).

When I initially rebuilt the Gripper Mechanism (http://jimsrock-ola1452.blogspot.com/2018/06/gripper-unit-assembly.html) I ran into a little issue with the new chrome on the Gripper Arm in that it didn't quite fit over the "boss", or "centering tab" of the Gripper Housing.

Here's another shot of that:

In order to make these two parts fit snugly, not only did I have to grind down the Gripper Arm a little (the chrome piece seen here), but I also filed-down the centering tab on the housing a little.

Granted, it really looks like crap (the Gripper Arm), but since it works I figured it was "good enough" for now.

Or so I thought......

Come time to load-up a couple records and see how the new mechanism works, and wouldn't you know it- the damn Gripper Arm doesn't line-up the record with the Record Tray, which is the same issue the old unit had back when I was a kid!

(And here I thought I was "this close" (thumb and forefinger) to putting the mechanism back in the cabinet!)

Since I've already fixed this issue (I'll get to this in a minute), and because I'm having a hard time explaining this properly, I just used my spare/"parts" 1452 to record a quick video about this which I've tossed-up to Youtube. In essence, when I got lazy and filed-down that "centering tab", I created my own problem. How? As the Gripper Arm rotates, there is a part on the rear of the Gripper Arm (the Gripper Arm Reversing Cam) which uses this tab to locate and properly align the Gripper Arm to the Magazine (old video of mine showing this here: https://www.youtube.com/watch?v=Vz5OImgxOJ0).

Any excessive play between the Reversing Cam and the centering tab will result in improper alignment (new video located here: https://youtu.be/gdM0yP6t9v0 ). And as I've shown, improper alignment can damage records.

And while I don't have the Spec for this, based on my recent experience I am going to define "excessive play" as meaning anything over 0.5 mm (half millimeter) between the Reversing Cam and the centering tab on the housing.

So how did I fix this? Well, several "quick fixes" came to mind, but since most of them were short term and temporary in nature, I didn't follow through with any of them. Thankfully I have some spare parts here, so ultimately I found the Gripper Housing with the thickest "centering tab", and decided to clean it up and use it instead of the original one.

And it just so happened that the thickest "centering tab" belonged to the Gripper Housing on my "parts" unit. Which meant I had to tear it apart:

 Clean it, paint it....

The new video showing the "play" in the mechanism was taken of this same unit (the parts unit), as it now has the original ("bad")  Gripper Housing in it, along with all of the dirty parts that I put back on it.

From here on out, every picture of the "actual"/restored unit in this Blog shows the repainted housing that I took from this unit.

Anyway, everything lines up perfectly now! 

And what about the Gripper Arm that I had filed-down? Am I going to use it?

Heck, no! Earlier this week I took an entirely different Gripper Arm (and mechanism) up to JR Custom plating (the chrome guys) in North Branch, showed them how all of this works, and explained why it is so critical that the final dimension between the two tabs is "exact". Johnny said he "got it", and that it would take them a couple weeks to re-chrome this new arm.

I told him to take his time, as I would rather have it done right, than done right now.

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!

Rebuilding the Dome Assembly

This is the point where I started to get really excited about finishing-up this project!

When I had all of the chrome re-done, I also had the all of the aluminum extrusions for the dome glass polished to a "show-like" shine. Not exactly OEM, but it's what I wanted. Don't like it? Sue me! 😁 (Actually, they may have been polished like this from the get-go, but I haven't been able to verify or disprove this.)

Originally Rockola used a sealant of some sort inside the frame channels/extrusions in order to hold the glass in-place, but I didn't want to make things "permanent". Knowing that I was using felt elsewhere in the jukebox (sourced from  Rockler, https://www.rockler.com/felt-tape-select-size-needed), I decided to give it a try here as well. Using 1/2" wide felt, I cut one piece to the correct length, and then I cut it in half along the length, which gave me the correct width (1/4") to fit inside both channels:

Then, working front-side-down, I installed the Dome Casting Assembly (which is specific to the 1452), and the Latching Bar mount:

After carefully sliding the Dome Glass (also specific to the 1452) in-place and installing the Lower Front extrusion (which already had a layer of felt), I found that there was a certain amount of "play" between the glass and frame, so I took it part, added another layer of felt in the frame channels, and reinstalled:

I got lucky, as it was a perfect fit!

Not wanting to scratch the glass, I took it out again and applied felt to the Dome Casting:

I put the dome glass back-in, installed some felt on the other/top side of the Dome Casting, and then very gently installed both Dome Upper Window Glass pieces (also specific to the 1452):

Everything still looked good, so I installed the Upper Front extrusion:

As well as the Dome Glass Backing Plates (left and right), which also had felt applied:

Once all of the frame pieces were in-place and there was little chance of the glass falling-out, I checked for "play" in the assembly: None, or at least dang near none! Now someone may want to argue with me about using felt instead of a sealant, but I feel that the results speak for themselves. Plus, should I ever need to take the glass out, I won't have to spend hours and hours scraping-off silicone.

Anyway, with the re-chromed hinge attached, and some of the Upper Selection pieces installed, things started looking really good!

Toss-in the re-chromed Upper Program Holder with some Title Strips:

  Spin it around and set it upright:

And you can see why I'm so excited now!

One last thing. I am assuming that most people who read this Blog are interested in Rockola's to some extent, and to these people I make this plea: If anyone knows where I can obtain a new piece of "Selections" glass, Rockola P/N 19355 (upper RH glass, two pictures up), please, please, PLEASE contact me! I have a spare/parts 1452 in the basement that I want to get running (but not restore), and this piece of glass is broken.