[Jukebox-list] Rockola 478 Reverse Relay. Chattering

[John D. Taylor III]

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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