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rockola 451

Posted: Fri Sep 09, 2011 1:23 am
by clones
Hi
have acquired a rockola 451 that was just about to be dumped, connected it up and the record magazine and turntable just keep turning, it will clock up credits and turn on "make selection light" but selection via the buttons doesn't work, selection via the movement of the wobble pins wont work either, on occasions the gripper motor will select a record and play it and return it to the magazine, but the turntable and record keep turning, any tips and advice

Re: rockola 451

Posted: Fri Sep 09, 2011 2:52 am
by Ron Rich
You will need to purchase a Service manual (see announcements--where to find--), and follow the sequence as shown there--
Something is failing to start the "basket motor". Ron Rich

Re: rockola 451

Posted: Fri Sep 09, 2011 10:21 am
by clones
sorry my mistake its a rockola 453 not a 451 probably not much of a difference, the record basket keeps turning also when service switch is on open

Re: rockola 451

Posted: Fri Sep 09, 2011 1:17 pm
by clones
just a further update, when selecting, buttons are held in, 1st and 2nd digit lights light up, then when third digit is pressed nothing happens, also just to note that the basket, turntable and carriage are constantly moving whenever the machine was turned on, what would be causing these to constantly move, is this an open circuit somewhere

Re: rockola 451

Posted: Fri Sep 09, 2011 4:58 pm
by Ron Rich
That would be a "closed circuit" somewhere--normal if any "pin was pulled" or the carry over switch on top of the pinbank was "stuck/bad"
Ron Rich

Re: rockola 451

Posted: Fri Sep 09, 2011 9:11 pm
by clones
Hi
thanks have sorted out the selection buttons, now i can make a selection and the write in carriage makes the selection, but the read out carriage is constantly moving around the wobble plate along with the turntable and record basket, have cleaned the outer and inner wobble plate printed boards and the contacts, also the readout carriage wont stop at any of the selections made, any thoughts on what may be causing this

Re: rockola 451

Posted: Fri Sep 09, 2011 10:24 pm
by Ron Rich
Sounds like you have two different problems--it is possible they are related to an open ground circuit.
Lets do these one at a time --verify that ALL pins are in the NON-selected position. Check the operation of the coil/switch located on top of the drum. It should be in the relaxed position, which should open the contacts on the switch. Check that with a meter. If open, power it up, and the RO arm should "park" near the bottom--if a 160 selection phono.
What/How did you "clean" the rings ?
BTW--that position on the service switch is not "open"--it's "operate" and it must be in "operate" in order to pick selections (Normal use position)---
Ron Rich

Re: rockola 451

Posted: Sat Sep 10, 2011 12:52 am
by clones
I checked the microswitch on the wobble plate and one of the connections was not connected properly, once that was done this stopped the read out carriage from revolving continuously, so now i can make a selection, the write in carriage will revolve and move the pin, the read out carriage will most of the time sound as if its about to move but gets tripped out,(i tried the brakers on the power supply but makes no difference) about every one in five selections when the read out carriage does revolve it wont stop at the selected pin, will just pass it and finish at the home position, i cleaned the wobble plate boards with denatured alcohol and some contact cleaner, any further thoughts

(have come across the RO carriage tripping before on later rockola models, found it to be anything from a loose relay in the selector unit, bad fuses in the selector unit and a faulty microswitch in the credit unit0

Re: rockola 451

Posted: Sat Sep 10, 2011 1:16 am
by Ron Rich
On the no scan start problem--usually find the copper "helper spring" on the start coil is broken, also have had bad coils--
On the read-out problem, -- have seen almost all you list, to a degree, and bad connection on the read-out "fingers" that ride the rings,
broken A-B snap switch, bad "contact" between the sensor and the (silver plated) spring holding it into the RO block. loose silver points on the "fingers",
Also have had them where NOTHING I did would have the "fingers", make good contact with the slip rings, till I cleaned it with DeOxIt.
Ron Rich

Re: rockola 451

Posted: Sat Sep 10, 2011 2:09 am
by clones
thanks Ron, will have another go at it tomorrow, 1am where I am at at the moment, will update the forum, thanks