rockola 437 readout pin on wobble plate not retracting

geschrieben von - posted by jewetttx 
rockola 437 readout pin on wobble plate not retracting
05.04.23 02:27
greetings guys from texas. its been a while. i put my tinkering on my rockola 437 on hold for a while because i got bored with it after many hours working on it, but have since started again . the only main problem im having left on this jukebox is the same i had when i last came onto this site asking for suggestions and that is that the pin on the readout side of the wobble plate wont retract causing the record that is playing when over to hangup and find the same record again and laying it back down on the turn table to play again. i know the #2 micro switch controls this and my switch was found to be good and even replaced just to make sure. i also checked both coils on the readout arms and they are both good registering 30 ohms each. and of course all the rings on the plate have been cleaned and polished, and wiper contacts cleaned many times. i feel there is just some little something somewhere that im missing. i had a jukebox guy up in Pennsylvania say it might even be in the mute relay? the only other place i think the problem might be is in the tone arm base maybe some how because i know when the record is set down on the the turn table this is when that coil on the readout arm is suppose to hit that lever pushing the pin back in, or the problem might be in the push button and number selection mechanism. i have taken the readout arms apart cleaned metal push arms and springs where the coils are housed and replaced the small metal contacs in these. still stumped since this long project started. hey jurgen02 buddy...u still out there for any additional help?
Re: rockola 437 readout pin on wobble plate not retracting
05.04.23 05:59
Hello to Texas again,
I am still around, no change to what I wrote last year:
"The reset coils are turned on just before the record is placed on the turntable cntrolled by a contact of Micro#2. Possible failures are Micro#2, A/B switch, connectors and wiring to the selector and the control box, interlock trip contact (in the control box) and the wiper contacts to the coils.
The coils are turned off after the tonearm moved down on the record and the gripper motor stops. In this position, a contact of Micro#3 turns on the interlock release coil, as a result, the trip contact opens the ground connection to the coils. "

No need to worry about the mute relay or tonemarm base.

You wrote Micro#2 is new and wiper contacts are all cleaned, have you also checked the Interlock trip contact, all contacts of the A/B switch and all connectors in between?
The attched picture shows the current flow in this moment, there are not so many options (connectors not shown in this diagram).

Are the levers moving a bit but not enough to reset the lever or are the coils humming when the tonemarm comes down? In that case, the problem could be that the -28V voltage supply is marginal.

Best regards Jürgen


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