My Rock-Ola 468 Not Cancelling Some Selections.

[doghouseriley]

This has been working well for years, (despite the problem I had with the carousel motor now cured).

On some selections close to each other on the wobble plate, it is now not returning the pin as it should.  I can see the little trip moving between the hammer and the plate, but it isn't returning the pin.

Any help would be appreciated.

www.youtube.com/watch?v=51ARnSMxgiE

[jukenorman]

I think the fist thing to do is clean the printed circuit wiper board on the read-out side - see page 12 of the manual.

Norman.

[doghouseriley]

Thanks for that, but I think I've sussed out the problem.
When the carousel is at rest, it's possible to rock it backwards and forwards by about a quarter of an inch or more.
I've found that on most selections the weight of the carousel is towards the back and the cancel function works fine. With the suspect selections the weight is to the front, consequently the little hammer misses the pin. If I push the carousel towards the back to take up the play and hold it there, it will hit the pin.

Is there any way to remove this play?

Also, the gripper arm isn't quite central, which I think is also down to this play, so some records when selected, like for those where the pin isn't cancelled, they rub slightly on the duck bills when selected and returned. The other selections don't touch the duck bills.

[jukenorman]

OK I was barking up the wrong tree! There's an adjustment for centering the gripper arm on page 62 of the manual. Before you mess with it, make sure that the read-out arm is tight on the shaft. That might sort out the cancel problem because I can't really see - if you can write selections OK - why they won't cancel, if the hammer coil fires.

Norman.

[doghouseriley]

Thanks, I've already tried that, but all it does is move the cancel hammer assembly. The carousel doesn't move.

Could it be anything to do with the gripper motor I recently took out and serviced, could there now be some play between the drive pinion and wheel?

[jukeboxmarty]

I fixed up the video link in the original post. It seems it was only allowing access by the video's creator.

Now we can all see it.

In the video the reset lever (hammer) is clearly missing the selection pin.

[jukenorman]

Yes of course it moves the cancel hammer assembly and along with that it moves the sensors that engage with the selection pins, so the point at which the dynamic braking of the carousel motor will take place should change, meaning that the carousel should stop more centrally with respect to the gripper arm. You have to make an adjustment and then try it out in order to check it. Did you also check for slack in the read-out arm on the shaft?

Norman.

[jukeboxmarty]

Jul 25, 2024 15:10:26 GMT doghouseriley said:

Could it be anything to do with the gripper motor I recently took out and serviced, could there now be some play between the drive pinion and wheel?

Did you remove the carousel motor? If you did, there may be too much clearance between the motor's drive (pinion) gear and the carousel's ring gear. The motor's mounting may need to be adjusted to eliminate any backlash.

[doghouseriley]

That's what I said, but I can't get the carousel to move, the screw indicated in the service manual isn't moving the carousel. If I were able to centre the gripper arm, there's more chance of the re-set hammer hitting the pin. It only started doing it a few days ago after I'd changed two or three records.

[jukenorman]

Yes but the screw doesn't move the carousel! The manual tells you which way to adjust it, you do that and then when you make the next selection, the position at which the dynamic braking takes place will be at a different point because the sensors which pick up the selection pins have been moved. It's a bit of an iterative process.

Norman.

[doghouseriley]

I've moved it both ways by several turns, but it has made no difference. The gripper arm still doesn't centre between the first and last records.

The hammer won't cancel the selections on lots of selections where the pins are nearest the front of the machine, but it will on selections on those pins on the far side of the wobble plate. If I could find a way to centre the gripper arm when it's at rest, it might start to cancel the pins that presently get missed by the hammer.

[jukenorman]

Did you check out Marty's suggestion of the carousel motor gears not being engaged correctly? I've now been able to look at your video - something must be slack somewhere because it is stopping in the wrong place! The reset hammer is directly above the sensor contact that initiates the stop (dynamic braking) and there is clearly some sort of over-run.

Norman.

[doghouseriley]

Jul 26, 2024 8:28:56 GMT jukenorman said:

Did you check out Marty's suggestion of the carousel motor gears not being engaged correctly? I've now been able to look at your video - something must be slack somewhere because it is stopping in the wrong place! The reset hammer is directly above the sensor contact that initiates the stop (dynamic braking) and there is clearly some sort of over-run.

Norman.

Thanks for that.

I answered my own question about that in my last post.

A case of me curing one problem and causing another.

I slackened off the three bolts that secure the carousel and managed to push it forward slightly. This removed the play in the carousel.

I also was able to stop the gripper brushing some records slightly against the duck bills by following the instructions in the manual. 

The gripper isn't exactly between the first and last record, but that obviously isn't a problem. I gave the carousel wheel a few drops of oil, not that it needed any.

All records now cancel as they should.

Thanks for everyone's contributions.

Working as it should.

www.youtube.com/watch?v=u2iCkF69EG8