Adjustment #5: Carriage Assembly (w/video)

Carriage Assembly Adjustments

A few Posts back I mentioned that, as a kid, the jukebox we had "ate" records, and I distinctly recall records scraping along the sides of the Record Keepers as they were going into, and out of, the Record Magazine. I'm almost certain that this adjustment, had it been performed properly, would have saved most, if not all, of the 45's I had as a child.

According to the IOM, the Carriage Assembly has three functions:

1. Search for a Selector Lever in the "Play" position, and upon finding one, stop the rotation of the Record Magazine motor,
2. Align (or "index") the Gripper Arm to the proper record,
3. Return the Selector Lever (see item #1) back to the normal position.

There are two rows of Selector Levers located around the circumference of the Selector Unit, the levers in the front row correspond to odd numbered selections, and the levers in the rear row correspond to even numbered selections. Regardless of row, a lever in the innermost position is considered to be "Off", while a lever in the outer position is considered to be in the "Play" position, as seen here:

On the bottom of Carriage Assembly are two spring-loaded contacts- one for the odd (front) levers, and one for the even (rear) levers (circled in yellow):

As the Carriage rotates over the Selector Unit, it will immediately stop the Magazine Motor when a contact finds a Selector lever in the Play position by short-circuiting the Magazine Motor armature (the Selector Lever in "Play" electrically "grounds" the motor). In the IOM this is referred to as "Indexing the Gripper Arm".

Also note in the picture above that these contacts are mounted in separate "blocks" that can be moved left to right independently. I will refer to these blocks as the "front/odd block" and the "rear/even block" in a minute.

On top of the Carriage are 4 screws that hold these blocks in place- the two towards the front (yellow) are for adjusting the odd selections, and the two at the rear (red) are for adjusting the even selections.

Also, there are allen head bolts located on each side of the Carriage (no picture, see video) for making minute L-R adjustments.

The adjustment procedure is a little tedious, and one must be finicky when performing it, otherwise damage could occur to the records. Be thorough and take your time here.

The procedure:

* If the Carriage Assembly has been replaced, rebuilt, cleaned, or in any other unknown condition, the "rough" location (L-R) will have to ascertained. Doing so requires removing all of the records, powering-up the unit, and making various selections, both odd and even numbered. The idea is to adjust the 10-32 bolts on either side of the Carriage so that the Gripper Arm is located roughly on the centerline of the record slot in the Magazine when in the rest/home position. You don't have to be exact here, just try get a good "average".

* Once this is set-up, leave the bolts alone! You won't be touching them again. 

* After this is accomplished, the Odd selections (only) need to be adjusted. First step is to install some old records, and then select record #1. Note the Magazine rotates in a CW direction when making odd selections (this matters when making the adjustments, and under normal Play conditions the records will Play from #49 down to #1). When the Gripper Arm begins to remove the record form the magazine (maybe about half-way out), shut the unit Off at the Service Switch and note the location of the record with respect to each side of the Keeper on the Magazine. Take notes ("tight LH side", etc), and then repeat this process for the #49 record, as well as one of the middle selections (23, 25, etc). The results should be somewhat consistent.

Here's what I was able accomplish with Record #1 (performing "odd" adjustments):

Note how the gaps on both sides are almost identical.

Depending on where the record is at (too far left or too far right) will determine which way to move the Carriage Assembly, as you are either picking up the record "too soon" in the Magazine rotation, or "too late". See below.

If the alignment is off (the record is not centered in the Keeper), you can correct for this by loosening the two front screws on top of the Carriage (yellow, above), and moving the "front/odd block" either left or right accordingly, as per my notes below. Note that the allen head bolt is to be used for this adjustment, and my advice would be to make small, incremental changes (one-half turn on the allen head bolt) AT MOST before re-checking!

Once the adjustment is set-up for the odd numbered selections, DON'T TOUCH THEM AGAIN!

* The procedure for the even numbered selections is the same, only now the Magazine will rotating in a CCW direction (under normal Play conditions the records will Play from #2 up to #50) , and you will be working with the two rear screws (red, above) on top of the Carriage assembly. Start with record #2, take notes, go to record 48 or 50, take notes, go to record 24 and take notes (etc.) Again, make small changes, be patient, and go slow.

At the end of the video I promised I would post the following information to help clarify this procedure. If you watch the video, here's the info I promised:

Odd Selections:
  - Front set of Selection Levers
  - Carousel rotates CW, from #49 down to #1

Record tight to the left side of Magazine opening:
- Carriage picking-up contact "too late"
- Adjust carriage to the right

Record tight to the right side of the Magazine opening:
- Carriage picking-up contact "too soon"
- Adjust carriage to the left


Even Selections:
- Rear set of Selection Levers
- Carousel rotates CCW, from #2 up to #50

Record tight to the left side of Magazine opening:
- Carriage picking-up contact "too soon"
- Adjust carriage to the right

Record tight to the right side of the Magazine opening:
- Carriage picking-up contact "too late"
- Adjust carriage to the left

After everything above has been accomplished, Best Practices would dictate that all Selections are checked (odd selections and then even selections), and VERY SMALL changes made to the Carriage so that a "best fit" is achieved for all records.

Be patient. Do this "right", not "right now"!


Link to video: https://youtu.be/QmWMJI2Lm8I

Adjustment #4: Micro Switches (w/two videos)

Micro Switch Adjustments, including:

• #3, Cancel Relay Micro Follow Switch  
• #4, Safety Micro Switch 

Seen below are two switches:

• The #3 Micro Switch, also referred to as the "Cancel Relay Micro Follow Switch", and
• The #4 Micro Switch, or the "Safety Micro Switch"

The #3 switch is located on the left (outboard), the #4 switch is located on the right (inboard), and both switches are operated by cams on the Gripper Drive Shaft.

Obviously both of these need to be "timed" to work with the Grip Cam Limit Switch properly, and thus that procedure needs to be completed before adjusting these two switches (see previous post for procedure). Also, if the Grip Cam Limit Switch is moved, replaced, or otherwise adjusted in any way, timing and operation for both of these switches will be affected.
 
Recall that the Grip Cam Limit Switch removes power from the Gripper Arm actuator (stops the Gripper Drive Shaft from rotating), and also note that both of these switches are mounted to that same shaft. This, it should only stand to reason that these switches need to operate at some point in time before the shaft stops turning...and that's exactly what happens!

Operation:

• The #3 switch closes the circuit for the Selection Lever Reset Solenoids on the Carriage Assembly (one each front and rear), and completes the Cancel Relay circuit, which locks the Cancel Relay "in" should power be interrupted for any reason.
• The #4 switch ensures that the Magazine Motor does not operate while the Gripper Arm is in any position other than "home".

The IOM calls for the adjustment of these switches to be performed while referencing the same Stop Pins mentioned in the previous post. However, because I prefer to not use the Stop Pins when adjusting the Grip Cam Limit Switch, I have found I achieve better results when I simply adjust them according to what I call "Actual" conditions, and that's what I am going to show here. If you have a copy of the IOM and prefer to use their method, so be it! But be aware that regardless of which method you use (IOM or Actual), you will need to consistent, as the switches don't always allow for a "mix 'n match" of the two methods.

Since it is the easiest to understand, and thus explain, I'm going to start with Switch #4. As stated directly above, the purpose of this switch is to open the circuit to the Magazine Motor so that it cannot operate any time the Gripper Arm is not in position above the Record Magazine. In other words, this switch operates so that any time the Gripper Arm has moved from this position, the Magazine Motor is effectively shut off.

In my opinion, adjustment of Switch #4 is most readily performed with the Gripper Actuator removed (as seen in the video) so that the Gripper Arm Shaft may be manipulated manually. The procedure is to manually run the Gripper Arm Drive Shaft through a full "cycle", and adjust this switch so that it closes (you will hear the click) just before the Grip Cam Limit Switch opens as the Gripper Arm is releasing the record back in the Record Magazine. If the Grip Cam Limit Switch opens before the #4 switch, the shaft will simply stop turning, and thus the switch won't have a chance to fall into the groove in the cam.

Note that you must run the mechanism through the full cycle during this procedure, as the Grip Cam Limit Switch must be in the proper position in order for this to work. If you simply turn the shaft, grab a record, raise the Gripper Arm a little, and then put the record back, this won't work, as you haven't reset the Grip Cam Limit Switch.

As a final test, the switch should now "break" (operate) when you manually turn the shaft at the beginning of a simulated cycle.

Once switch #4 is properly set-up, adjustment of switch #3 is downright simple. As mentioned previously, this switch has several functions, one of which is that is enables/energizes the Selection Lever Reset Solenoids (which are de-energized/shut-off by the Grip Cam Limit Switch). Checking the operation involves little more than listening to the timing of these solenoids (more on this below).

I didn't mention this in the video, but my method of adjustment is as follows: Rotate Switch #3 into position so that there is a 1/8" gap between the two cams in the groove shown here, and tighten the set screws.

Rockola's IOM describes this adjustment this way: "Loosen the set screws in the #3 micro cam and rotate it so that it is flush to the adjacent #4 micro cam, and the gap distance between the two interlock edges is 3/16 of an inch". Sure, sounds simple enough. But since the edges are rounded, where exactly is this dimension supposed to be measured? At the beginning of the radii, or the end?

I prefer to use the 1/8" allen wrench method, making sure it's bottomed-out onto the shaft.

Thankfully this adjustment isn't as critical as the previous, and most of the time the 1/8" allen wrench setting will suffice.

To manually check this setting/adjustment, while operating the Gripper Drive Shaft manually, turn the shaft so that the Gripper Arm rotates down into the Play position, but with the record still in its grasp. While continuing to rotate the Drive Shaft so that the Gripper Arm begins to open, Switch #3 should fall into the cam and "click" at some time prior to the Grip Cam Limit Switch.

If things look good, power the unit up, check your setting/timing against mine (time stamp 3:50 in the second video linked below) and adjust accordingly.

Having said that, I can say with absolute certainty that I have this switch adjusted exactly the same as the 1452 we had when I was a kid, as this is a sound I have never forgotten, seeing how it was burned into my memory during my young, formative years!

Due to time constraints (length of video), I broke-down these adjustments into two videos, one showing the actual adjustments, and the other showing operation and some other details.

Link to first video (adjustments): https://youtu.be/SrCXQmsMU6s

Link to second video (proper operation): https://youtu.be/hYcGSJD5hzc

Adjustment #3: Grip Cam Limit Switch (w/video)

Grip Cam Limit Switch Adjustment

At the risk of being overly simplistic, the Grip Cam Limit Switch (shown below) controls the amount of travel of the Gripper Arm (along with several other things that I wouldn't go into here). In other words, it controls the amount that the Gripper Arm opens, both in the "Home" position (my term) as well as in the Play position. It is a snap-acting switch controlled by two cams: the Grip Cam Outer, and Grip Cam Inner.

The "Outer" cam controls the amount of stroke in the Play position, and the adjustment screw is seen here (circled in orange):

The "Inner" cam controls the amount of stroke in the Home position, and the adjustment screw is located almost 180 degrees opposite (circled in yellow):

For adjusting purposes there are two of these "Stop Pins" provided, one located on the Gripper Housing, the other located on the rear flange of the Gripper Drive Shaft.

Here is a picture of the two pins when the Gripper Arm is located over the Record Magazine (Home position):
 

Inner Position

And here is a shot of the same two pins after the Gripper Arm has rotated over into the Play position:

Outer Position

Note there is a difference in the gap between the pins in the the two positions. More on this in a minute.

With regards to adjustments, the IOM states, "When the gripper arm is in the rest position over the record magazine, the cam shaft should be stopped so that there is approximately 1/4" opening between the two stop pins....". Now this is all Fine and Good, but what it doesn't say is that the Gripper Arm will continue to rotate a little when the motor shuts off, so be aware that adjusting the Inner Cam based on manually rotating the Gripper Shaft will result in a misadjusted switch! You may have to revisit this cam a couple times in order to get it to switch right where you want it.

Looking up to my "Inner Position" picture, one may see this as a 1/4" gap, based on this angle, but in reality it is larger than that.

The IOM also states, "When the gripper arm is in the turntable position, the cam shaft should be stopped so that there is approximately a 1/4" opening between the two stop pins". Now on this one I will take an extreme exception to, as there's no way you can adjust the Outer cam to get this gap once you've properly set the Inner gap! Why? It's easier to show this in the video, but the reason that this is impossible to achieve is that the two cams "push" against each other. To help explain, look at this picture, particularly what I have circled:

Setting aside which cam is which right now, let's say in the picture above that you need to adjust the "upper" cam in a CCW direction a little. Well, you can't, as the "lower" cam is blocking it from rotating any further (it is "pushing" it). Likewise, if you needed to adjust the "lower" cam in a CW direction just a little, you wouldn't be able to, as the "upper" cam is in the way.

Bringing this back to the Real World, adjusting the Inner Stop Pin gap to 1/4" means that the Outer gap is going to be wider (the Inner cam will "push" the Outer). And adjusting the Outer Stop Pin gap to 1/4" means that the Inner gap will be wider. This is why the IOM is a little, "optimistic", when it comes to adjusting both cams to a 1/4" gap, as there's simply no way to do it!

But thankfully you don't really need to set them this way. Why?

Recall that the purpose of the Grip Cam Limit Switch is to set the amount of travel (or "inner width", if you will) of the Gripper Arm in both the Play, and Home, positions. In other words, this switch shuts-off the Gripper Arm actuator when the proper amount of opening has been achieved in either/both positions.

Thankfully there is some "play" in the system, and by that I mean that near the end of it's travel, additional rotation of the Gripper Arm Shaft doesn't equate to more opening (width) of the Gripper Arm. (Go ahead and read that again, as it may be one of the more important parts of this Post.) You should be able to adjust both cams so that the Grip Cam Limit Switch changes over at the exact point that is best for your particular set-up.

Don't worry about where the Stop Pins are "supposed to" end-up according to Rockola, but rather, pay more attention to where the Gripper Arm needs to be at it's widest- during the Home position, or during the Play position. On this particular unit, I found it best to "advance" the cams a little so that the Gripper Arm is at maximum width when it is in the Home position.

Don't get me wrong here. I haven't sacrificed the action of the Gripper Arm during the Play position, as it definitely opens wide enough, but rather I found that due to my use of the non-original Gripper Housing (see my "Setback" post), I preferred to "cheat" the cams just a bit and prioritize things so that I got the maximum opening possible when the Gripper is over the Record Magazine. 
 
This all may be easier to understand in the video:

Link to video: https://youtu.be/BnEbcBs6NLc
 

Adjustment #2: Grip Cam Limit Switch Mounting/Location (w/two videos)

Grip Cam Limit Switch Mounting/Location (switch position)

This procedure gets only a one-sentence mention in the IOM, but I feel it needs to be discussed in more detail in order to save on wear and tear on the equipment. Let's face it, this unit is currently 64 years old, parts are getting harder and harder to find, and I see no sense in subjecting anything to unnecessary abuse.

Before adjusting the Grip Cam Limit Switch, the physical location of the switch needs to be adjusted front-to-back so that a pin located on it (circled below) is properly located. This pin is located here:

Here is a side view of that same pin:

That pin needs to be located close to the wall it rides next to (and the groove it sometimes rides within), but it should not touch it/them. Normally this would not be an issue, as one could "set it and forget it", but partway through the Gripper Arm rotation, the pin is going to come across a section where there are two thicknesses of "wall", and we don't want it to hit/ride against anything as that will cause wear.

Here's what I am referring to:

To quote the IOM, "The Cam Pin of the Grip Cam Limit Switch should be located so that there will be equal clearance between the barrier walls at the point where they overlap, when the Cam Pin is in the inner and outer position".

They make it sound like the pin itself is adjustable, but I think what the writers mean to imply is that the switch location is adjustable.

Screenshot from the video showing the location of the Grip Cam Limit Switch mounting bolts:

 
I could try explaining this all day, but perhaps the best way to see this is to watch the videos.

Link to set-up video: https://youtu.be/bQ2IAd7cQ1A

Link to video showing proper operation: https://youtu.be/AlByOj2GLBs