[Jukebox-list] Rockola 478 Reverse Relay. Chattering

Mon Dec 3 18:25:03 PST 2007

John - I don't have that manual, nor have I worked on a machine that new. 
But I've seen this problem on an earlier Rockola, and it was those contacts 
on the reversing relay. Even if you buy a burnishing tool and clean them, 
you should check the resistance with a meter to be sure. Usually when you 
see a relay chattering, the contacts will arc or smoke. This is why I 
directed you towards the contacts, plus the fact you said it worked if you 
pressed it by hand. Pressing it by hand may be allowing the armature to move 
differently, thus making better contact.

Once activated, the reversing relay is held in by one of the contacts on the 
relay itself. After a few revolutions of the gripper motor, microswitch #3 
parallels this contact. Microswitch #1 is also in this circuit, as is 
another set of contacts in the reversing relay, and the interlock release 
relay contacts inside the control box (if your machine has one - like I 
said, I've not worked on that model). Check all these and you should fix the 
problem. Good luck,

Jim

PS - the earlier Rockola manuals give really good sequence diagrams - 
simplified schematics along with written explanation for each point in the 
mechanism cycle. I would invest in one.

----- Original Message ----- 
From: "John D. Taylor III" <johndt3 at verizon.net>
To: "Jukebox mailing list" <jukebox-list at lists.netlojix.com>
Sent: Monday, December 03, 2007 6:42 AM
Subject: RE: [Jukebox-list] Rockola 478 Reverse Relay. Chattering

> Thanks for your suggestion Jim,
>
> I thought the samething.  Unfortunately, I did not have eight burnishing
> tool to clean the contacts like it should be done.  The point file is too
> thick to get in between the contacts.  I did take a scribe and clean them 
> as
> well I could and then reformed the contacts on the bottom side of the 
> relay
> so that they would make just a split second sooner.  I had also found on
> another forum someone that had this same problem, and although a person
> never did give a solution, he or she did say that they changed the 
> mechanism
> power Board, but the problem remained.  There is a delay module in the
> circuit that I really don't understand.  It is all part of the reverse 
> relay
> circuit, it is in a sealed package.  The package is labeled,(P.E.C. 301. .
> Nevertheless, if the mechanism power Board was changed by the person that
> posted the message and it did not change the problem than that package is
> not going to be the problem either.  I realize that that's an assumption 
> on
> my part.  I will pick up a burnishing tool and redo the contact on the
> relay, but before I go back I was hoping that someone could explain to me
> the purpose of that package.  Also, understanding the sequence of 
> operations
> in the circuit would go a long way towards clearing up the fuzziness that 
> I
> have in this tired or brain. Do you have a manual on the 478?
>
> Thanks
> John
>
>
>
>
>
>
>
>
>  -----Original Message-----
> From: jukebox-list-bounces at lists.netlojix.com
> [mailto:jukebox-list-bounces at lists.netlojix.com]On Behalf Of
> dirksenj at bellsouth.net
> Sent: Sunday, December 02, 2007 10:29 PM
> To: Jukebox mailing list
> Subject: Re: [Jukebox-list] Rockola 478 Reverse Relay. Chattering
>
>
> I would suspect the contacts on the relay itself.
>
> Jim
> ----- Original Message -----
> From: "John D. Taylor III" <johndt3 at verizon.net>
> To: <jukebox-list at lists.netlojix.com>
> Sent: Sunday, December 02, 2007 6:57 PM
> Subject: [Jukebox-list] Rockola 478 Reverse Relay. Chattering
>
>
>>
>> Greetings all,
>>
>> I have recently ran across a 478 Rockola reverse relay that chatters when
>> trying to pick the record up to return it to the magazine.  During this
>> chatter, the gripper motor jerks in time with the relay until the record
>> is
>> returned to the magazine.  This is a very slow process.  Unfortunately, I
>> am
>> not as familiar with the circuitry on this jukebox as I would like to be.
>> I
>> pulled the mechanism power Board  checked the relay along with the
>> components in the related circuitry.  All appeared to be well, with the
>> exception of two capacitors that were only a little out of
>> tolerance,-which
>> I replaced.  I noticed that when the record is canceled using any of the
>> cancel options if I activate reverse relay for a half a second with my
>> finger, then, it will stay activated until the cycle is complete.  During
>> half sec that I am holding relay in by hand the transfer arm has not 
>> moved
>> yet, so, none of the micro switches has changed position while I am
>> holding
>> it manually. The relay is self holding by the time the transfer shaft
>> begins
>> to turn within the cam switches on the end. I did found one forum where
>> another mechanic had the same problem, he changed the mechanism control
>> Board completely, but it didn't fix the problem for him, so I think I can
>> eliminate the board.
>>
>>
>> Okay, since I may have made this a bit confusing, I'll summarize.  When a
>> record is canceled the gripper motor begins a jerky movement to pick up
>> the
>> record and return it to the magazine, and a reverse relay is chattering 
>> in
>> time with the jerk movements of the gripper motor.
>>
>> I have the schematics, but not the manual.  I really don't understand the
>> sequence of operations on this jukebox.  However, I do have a schematic,
>> and
>> I have tried to chase the circuit's all around this 9 foot square thing,
>> this is when I realized I was in trouble and needed to ask for help. Can
>> anybody help me with this problem?  Can you tell me the sequence of
>> operations for the circuit? Have you ran into this before and know the
>> solution? I welcome any thoughts, and/or debates relating to this 
>> problem.
>>
>> Thanks to whoever created this forum, it's been a great help to me in the
>> past and I'm sure it will in the future.
>>
>> John
>>
>>
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>
>
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