Rock-Ola 496-1 problem/issue

Hi Patrick,
I may be confused here, but my vision is that the gripper bow is touching the turntable, rather then "flipping" one side of the record or the other to a horizontal position, as it must do prior to installing the record onto the turntable.
If that's the case, I can see nothing but a mechanical failure here--nothing "electrical" (other than the motor, of course) is involved in that process ??
Ron Rich

Ron: I reread the thread but I'm not sure just where he's at with this. I didn't realize it's still striking the turntable. That being the case, I'd suspect the placement of the gears if the bow's not frozen. I was thinking about the basket rotating endlessly past home without starting the gripper. I agree if it's not right mechanically, not much else matters.
Patrick

Hi Patrick,
Yea--I'm at a loss too--that's why I wrote "I'm confused"---time to go back to {} one on this one--
Ron Rich

WOW! My first try at fixing a juke and the problem is stumping two experienced guys who are nice enough to try and help!

sigh

For the record, Microswitch 1 appears to be in the notch when the arm is over the magazine.

Does a flow chart exist that lists exactly how the gripper functions, step by step, from beginning to end? Boy, would something like that help me to diagnose this issue!

Maybe do a video clip of what is happening(or not happening), its one of those things that is hard to visualise the problem. Cycle the gripper manually by removing or loosening the motor so the process can be seen in sort of slow motion
clones

Very little time on the juke (my home computer died), but I was able to make one new observation:

With the scan switch in the OPERate position, and by turning the gripper motor by hand, I advanced the assembly until the arm had placed the phantom record onto the phantom turntable platter. I then manually triggered the upper microswitch located on the tonearm bracket and the gripper picked up the 'record' and returned it to the magazine.

I'm wondering if it's possible that someone trying to repair the juke, might possibly have reversed the wiring on that microswitch? Could that cause the magazine to continuously turn? Without having a 'Theory Of Operation', I don't know what item tells another item to do something (if you know what I mean).

I'm thinking/hoping this might possibly be a major clue.

What do you folks think?

As always, thank you for any assistance,
Steve

Steve,
Did you purchase a service manual package, from one of the "ligit" sources listed above ? If so, it "shooda-had" a large schematic with it--
My great, but not too long memory, says that the schematic is marked with wire colors--If so, you can see how all switches were connected-- Ron Rich

Hi Ron,
Yes, I do have a schematic (large, double-sided, possibly an original) but I couldn't locate the microswitch. My eyes aren't what they once were so I probably missed it.

In talking to some of the engineers here at work, crossed wires on the switch could absolutely cause it to operate backwards (i.e. 'Open' would be 'Closed' and vice versa.

This could very well be the key to solving the problem. I'll let you know.

Patrick, how are the wires connected on your 496?

I made a video of the symptom in action and posted it on YouTube. It's Hi-Def, more out of inexperience than need. Here is the link:

http://youtu.be/5hsNHt2Hejs

I tried to capture as much as possible. I hope this helps someone.

Thanks!

Hello Steve
I think your problem might in the Power P.C. Board Assembly-Mechanism Part # 55180. I had a similar problem and traced it to the two 22 mf 35 volt capacitors located in position 54374 and also the .1 mfd 20% capacitor located in position 52382.
This information is on page 31 of the Rockola #496 Parts book.
It also sounds like you should tighten up on the strap that holds the records in the basket.
I have a few Rockola’s that I run 50% full and have never had records get destroyed the way you have described.
Hope this helps
Bud

Hi Bud,

Thanks for chiming in. You had a similar issue, eh? Don't take this the wrong way, but that's great! ! I'll look at the circuit and replace if necessary. Normally it's electrolytic caps that go bad, but I doubt there would be any in this part of the circuit.

I have adjusted the magazine strap per the adjustment manual (3/32 clearance for bottom record w/full magazine, if memory serves), but that might have been after I recorded this.

Thank you very much for your input! I appreciate it very much.

Steve: I've been away and just catching up now. Saw your video. Outstanding, clean machine on the inside!
Your wires to the No. 1 micro appear to be correct: red/blue on top, green/blue in the middle, and pink/blue below. Again, if you've not removed and cleaned all six connections and checked the micro with an analog meter as described in one of the "stickys" here, I'd do so. The angle of the camera keeps the roller and notch out of sight behind the 1/4" screw head at the tone arm pivot, so I can't tell from that if it's timed correctly. It's not just that the roller needs to be in the notch with the bow over the magazine; but, when the bow settles over the magazine, continue to turn the knurled shaft on the gripper motor (assuming it's connected) until it's tight (don't force it). THAT'S when the roller should just drop into the notch. Similarly, if you twirl that shaft until it places a record onto the turntable, keep turning as it feeds the tone arm onto the record. If it won't do all that then the gears might not be timed right. But they do look very near where mine are at rest. Note that there should be a flat washer and screw at the end of the outboard gear facing the camera. Good luck; you've got a really nice machine. It's just making things interesting so that you'll appreciate that big sound when it all comes together.
Patrick

Thanks for the response, Patrick! First, yes, there is a flat washer and screw for the outboard gear. They weren’t on when I filled this.

If I understand your explanation of the event timing, if I am turning the motor by hand, just as I reach the ‘end’ of the cycle and the motor can no longer be turned, the #1 (top) micro arm should drop into the notch at that moment. Well, I can tell you that that is not how mine is operating! I can continue to turn the motor, and thus the gears, long after the micro drops into the valley. I can turn until the micro arm is up against the wall at the far end of the notch. Does this make any sense to you? If so, how would I correct the timing events?

I will try to get a video showing the cycle from when the notch drops so you can see what I’m talking about. I think I will need a helper to either record or turn the motor.

Thanks for your help,
Steve

Steve: at that point we're discussing, my roller is at the left side of the notch. With the switch open in that position (and if all else is right) the carriage motor will operate; closing the switch will disconnect the carriage motor and kick on the gripper motor as the cam turns. If adjustment is needed, there are two Allen screws in the cam fastening it to the shaft.
Patrick

This is actually starting to make a small bit of sense to me. In its current condition, with the magazine and TT turning, they will both continue to turn endlessly. If I manually lift (close) the #1 micro (whose tip is in the notch), the magazine stops turning for as long as I keep that micro closed. The gripper cycle is not initiated. That tells me that it is a different cam and/or micro that activates the gripper cycle. Remember what I reported previously in this thread? After manually advancing the gripper motor through its cycle until the phantom record was placed on the TT, I was able to activate the gripper cycle by ‘closing’ micro #1.

I know I’m a rookie, but this leads me to think that the problem could very well be caused by a timing issue, i.e.: a cam is not activating a micro at either the proper time or at all. Or a bad micro.

Or am I way out in left field?