[Jukebox-list] Rockola 478 Reverse Relay. Chattering

[John D. Taylor III]

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