Rockola 429 blowing "lights" fuse, upper left on service/control module

Hi,
I've been working on a Rockola 429 "Starlet" for some time now. The
initial problem was the record would not reject until I turned the
gripper motor by hand, and then everything would kick in normally,
until the next record would be brought out to play. Then the process
would be repeated.
I cleaned the gripper arm motor, as well as the selector disc (and
reset coils)/"wobble plate". I then (through the help of my friend
William), found a burned out resistor in the junction box under the
mech, which I replaced with one of an exact value I had. All was fine
for about six weeks.
Then a part of the tonearm which follows the tonearm cam became bent,
which we straightened......even replaced the gripper arm assembly with
an entire new one. It moves freely. This was replaced because a "stud"
that prevents over-travel of the gripper arm was found to be missing
from the mech assermbly.
Once replaced, I put it into the 429, and everything seemed to be okay,
until I put the service switch into the "operate" position........it
blew the uppermost left-hand fuse in the rear right of the jukebox
cabinet. This fuse says (paraphrasing) "117 volt lighting". It blows
each and everytime now; but only when the service switch is put into
the operate position.
Where do I begin to look......I don't feel it has to do with the
lighting, as that was never touched! Is the problem still in the
junction box, where I changed the wire wound resistor? Or could it be
in the newly replaced gripper arm assembly we installed, even thougfh
it is operating as it should, with no binds in it? I have also checked
the three microswitches, and they seem to be operating as they normally
should. Please help! Rob

Rob,

If I was at the box, I could probably be more useful. The 429 was a little before my time and I've not had the privelege of working on one.

That said, are there any animations such as pilasters or color wheels that might be inhibited while the service switch is in the off position? Do the lights work until you place it in the play position. ( I know that when you have been through as many trouble faults as you have here that you sometimes forget minor details that might help troubleshoot )

After being blown, if the fuse looks "blackened" inside the glass, it was terminated with extreme prejudice. Otherwise known as a direct short to return or ground. You could start by visually inspecting all harnessing for lost insulation and or being pinched underneath the case of a mounted assembly. Do you have a schematic for this machine?

Lastly, try disconnecting the flourescent and any other line voltage lighting and recheck. A good trick here is to purchase a resettable circuit breaker of the same value as the fuse and hook it in at the fuse block. You won't go through 10 or 20 dollars worth of fuses. You can also unhook other connectors until you find one that affects the short condition.

Wish I could just say, "Look for the purple / white wire and .... " , but this one will take patience and discovery.

Hi DRebber,
Thank you for replying. There are no animations, be it pilaster lights
or color wheels. The (fluoreswcent) lights DO work until I throw the
service switch in the operate position.
I believe the fuse looks blackened inside, indicating a direct short. I
do feel it has been a direct short from the start (that is, since
putting the mechanism back into the cabinet, after putting the
different gripper arm assembly on the mechanism).
I suppose when my friend did re-install the mechanism, he could have
pinched a wire somewhere. I will go back to his house in a couple of
days and examine it from head to toe, to look for this. Part of the
problem with this is, I'm approaching it with the "Seeburg" attitude of
being able to place it in play by manually tripping the trip lever
while it is scanning. Of course, being a Rockola, this is impossible to
do so; it's either in scan, or it's in operate (unless it's
service/off). And of course, as soon as I do put it into operate,
BAM!....the fuse blows and the lights all go off.
I do not have a schematic for this particular model, although I do have
manuals for several other Rockolas, both before and after this model. I
do NOT like the way Rockola does their "sequence"
illustrations/diagrams. And I do not like that they do NOT have a
troubleshooting guide to help narrow down problems encountered. This in
part is why I posted such a basic question to this site/group. My
knowledge in electronics/reading schematics is basic, at best.

One final question: in trying to narrow this down, is it best to start
with everything disconnected with all the fuses good, and then connect
ONE at a time, such as lighting, turntable motor, selector, amplifier,
etc.? Or is it better to leave it as it is, and disconnect one
plug/connector at a time until the fuse stops blowing, and then attempt
to trace that circuit out on a schematic to see what the possible
entities in the circuit are blowing the fuse in question? I will do
what you say. Thanks again, Rob
DRebber wrote:
Rob,

If I was at the box, I could probably be more useful. The 429 was a
little before my time and I've not had the privelege of working on
one.

That said, are there any animations such as pilasters or color wheels
that might be inhibited while the service switch is in the off
position? Do the lights work until you place it in the play position.
( I know that when you have been through as many trouble faults as you
have here that you sometimes forget minor details that might help
troubleshoot )

After being blown, if the fuse looks "blackened" inside the glass, it
was terminated with extreme prejudice. Otherwise known as a direct
short to return or ground. You could start by visually inspecting all
harnessing for lost insulation and or being pinched underneath the case
of a mounted assembly. Do you have a schematic for this machine?

Lastly, try disconnecting the flourescent and any other line voltage
lighting and recheck. A good trick here is to purchase a resettable
circuit breaker of the same value as the fuse and hook it in at the
fuse block. You won't go through 10 or 20 dollars worth of fuses. You
can also unhook other connectors until you find one that affects the
short condition.

Wish I could just say, "Look for the purple / white wire and .... " ,
but this one will take patience and discovery.




--
DRebber

Rob,

This gives a much clearer picture of the problem. My first guess (outside of what I've already guessed) would be the turntable motor. It is 110VAC and runs anytime the mechanism is active. OR..... at least that is the way they did it on the later vinyl boxes

Rob, see if the wires that go to the turn table are shorted.
Mark
wrote:
Hi,
I've been working on a Rockola 429 "Starlet" for some time now. The
initial problem was the record would not reject until I turned the
gripper motor by hand, and then everything would kick in normally,
until the next record would be brought out to play. Then the process
would be repeated.
I cleaned the gripper arm motor, as well as the selector disc (and
reset coils)/"wobble plate". I then (through the help of my friend
William), found a burned out resistor in the junction box under the
mech, which I replaced with one of an exact value I had. All was fine
for about six weeks.
Then a part of the tonearm which follows the tonearm cam became bent,
which we straightened......even replaced the gripper arm assembly with
an entire new one. It moves freely. This was replaced because a "stud"
that prevents over-travel of the gripper arm was found to be missing
from the mech assermbly.
Once replaced, I put it into the 429, and everything seemed to be okay,
until I put the service switch into the "operate" position........it
blew the uppermost left-hand fuse in the rear right of the jukebox
cabinet. This fuse says (paraphrasing) "117 volt lighting". It blows
each and everytime now; but only when the service switch is put into
the operate position.
Where do I begin to look......I don't feel it has to do with the
lighting, as that was never touched! Is the problem still in the
junction box, where I changed the wire wound resistor? Or could it be
in the newly replaced gripper arm assembly we installed, even thougfh
it is operating as it should, with no binds in it? I have also checked
the three microswitches, and they seem to be operating as they normally
should. Please help! Rob