Rock-Ola 451 magazine not rotating in Scan position

[stratfordade]

I've created a new problem on a Rock-Ola 451 I've been trying to fix. The original problem was that all operated correctly, except that at the end of the record the gripper arm failed to pick up the record from the turntable, before moving back to standby position. My diagnosis was that the gripper mechanism was sluggish and not moving in fast enough towards the turntable to grab the record before the bow rotated back towards the magazine.

So I disassembled just the plunger, spring, gripper arm and reversing cam by knocking out the lock pin (I didn't touch the gears or trunnion assembly) and disconnecting the gripper from the motor so I could rotate the arm to remove, cleaned these up, then oiled them and reassembled. However I had not pushed in the reversing cam quite far enough along the rectangular bracket it sits on, so that the gripper bow jammed as it moved upwards towards the turntable, as the reversing cam didn't rotate properly off that rectangular bracket. I've now got that cam in the right place so that it moves freely on and off the bracket, but since then the magazine will no longer rotate (even if I just move switch to Scan) and the gripper motor doesn't turn after I've made a selection (the carriage rotates over selector wheel and stops correctly).

I've got the service manual and troubleshooting guides. It suggests pressing the mechanical reset if the magazine motor won't rotate. I've pressed the mechanical reset I can see but it makes no difference — still no power to magazine motor or gripper motor. Does the jukebox need to be powered up for the breaker to reset? Does it take a firm push?

All was pretty much fine before I broke it! So I'm thinking that when the arm got stuck either a fuse blew or some circuit breaker tripped. I suppose the gripper motor could have been damaged but the fact that the magazine motor won't turn points to some main power problem. Please can anyone advise which fuses I should be checking, and what the procedure is to reset the mechanical breaker?

Thanks a lot!


 

[Ron Rich]

Circuit ("mechanical") breakers (CB) can be reset with power on,or off, by just "pushing them in". HOWEVER if the reason it "popped" is still there, it will re-pop instantly. Move the gripper motor away from the gears, and press that CB again. Too bad you did not read the above sticky post on "gripper problems" as you could have easily "fixed" that problem, without dis-assembly. Ron Rich

[stratfordade]

Thanks Ron and yes I only discovered that sticky today after encountering this problem! I'm not even sure the CB has popped — I couldn't feel or hear any click pushing the red button in — but there does seem to be a fundamental power issue if the magazine motor does not run even with the Scan switch. I will go back to studying the service and troubleshooting manuals and circuit diagrams to look for more clues — I'm more an electronics than electromechanical guy. The machine's elsewhere but next time I take a look at it I will check carefully whether the CB is popping as soon as pushed in, and if so try your idea of moving gripper motor away from assembly in case that's jamming up.

[Ron Rich]

it can not "scan" until the gripper cam is totally in the "home position". Ron Rich

[stratfordade]

Ah that makes sense of what I see on the circuit diagram, and points me to what I should check when next working on the 451. How does the machine 'know' it's in home position? Thank you!

[Ron Rich]

One of the cam switches informs it-- If not totally "homed" the gripper can "catch records" as they pass it-- not a very good idea ! Ron Rich

[stratfordade]

Thanks. That would thin out someone's 45 collection!