old turntables

[dallie]

alright i have a very old turntable that was probably made in the late
1960s. whenever i play a record the needle always stops moving on the
record, usually in the middle of the last song. i have tried other
records but it always stops in the same place. it feels like there is a
spring mechanism that keeps it from moving in all the way in. so my
question is what is causing this to happen, and how can i fix it. just
please dont tell me to buy one of these new ones.

 

[Dave Plowman (News)]

alright i have a very old turntable that was probably made in the late
1960s. whenever i play a record the needle always stops moving on the
record, usually in the middle of the last song. i have tried other
records but it always stops in the same place. it feels like there is a
spring mechanism that keeps it from moving in all the way in. so my
question is what is causing this to happen, and how can i fix it. just
please dont tell me to buy one of these new ones.

On some types the arm touches a lever at the end of a record which then
triggers a lift mechanism. Make sure that lever is free moving. Could also
be problems with the arm bearings, bias compensation, or incorrect
tracking weight.

 

[ian field]

alright i have a very old turntable that was probably made in the late
1960s. whenever i play a record the needle always stops moving on the
record, usually in the middle of the last song. i have tried other
records but it always stops in the same place. it feels like there is a
spring mechanism that keeps it from moving in all the way in. so my
question is what is causing this to happen, and how can i fix it. just
please dont tell me to buy one of these new ones.

Could be a jammed auto-changer trigger.

 

[Sam Goldwasser]

On some types the arm touches a lever at the end of a record which then
triggers a lift mechanism. Make sure that lever is free moving. Could also
be problems with the arm bearings, bias compensation, or incorrect
tracking weight.

Most likely gummed up grease on any or all of those parts.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
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[Mark D. Zacharias]

Could be a jammed auto-changer trigger.

Could be wires bound up underneath or bad tonearm bearing(s)...


Mark Z.

 

[b]

alright i have a very old turntable that was probably made in the late
1960s. whenever i play a record the needle always stops moving on the
record, usually in the middle of the last song. i have tried other
records but it always stops in the same place. it feels like there is a
spring mechanism that keeps it from moving in all the way in. so my
question is what is causing this to happen, and how can i fix it. just
please dont tell me to buy one of these new ones.

if its an autochanger (such as a garrard or bsr), unclip the
turntable's central c-ring/ clip and remove the platter itself by
lifting straight up. Look for a large metal toothed cam. unclip the
c-ring carefully, and lift off the cam. you may feel resistance, thus
revealing the problem: gummed up due to dried grease. More importantly,
there will probably be a smaller set of moving plates affixed to this
cam which will need checking and removing.

I have usually found it best to remove these parts, clean the bearings
and any shafts with alcohol and a q tip then regrease (NOT wd40!!).
hope this helps, let us know how it all goes.
-Ben.

 

[jakdedert]

Could be a jammed auto-changer trigger.

Could be wires bound up underneath or bad tonearm bearing(s)...


Mark Z.

I think Sam and a couple of others nailed it. Grease drys up and makes
things bind. The lever which trips the 'rejuct' mech' on those old
changers is definitely suspect; but I imagine the rest of the guts are
just as gummy.

For a novice, these are not the easiest things to work on. The timing
of the cams is similar in some ways to a VCR. Get it wrong upon
reassembly, and it won't work.

jak

 

[[email protected]]

dallie:
If you are mechanically inclined in the least, you should be able to
LOOK at the mechanism under the platter and on the underside of the
turntable and SEE what is hanging up.
As others have indicated, could as simple as dried up grease causing
stiff bearings and spindles, stuck or sluggish cam and levers, stuck
end of record trigger mechanism, and possibly bent levers, etc. You
should be able to move the arm around and determine what the problem
is.
You would be very wise to remove the expensive needle (stylus) while
analysing this problem so you don't accidently damage it.
If you are still not certain how to proceed with this repair you should
TAKE it to a repair shop that services this type of item.... my shop
does... and many smaller, owner operated shops will still do this kind
of work....... if you screw it up more than it already is, the repair
cost could be much higher.
electricitym
..
..

 

[[email protected]]

Mechanical problem is very likely, but if not, then I would guess dried
out electrolytic caps. Although there aren't as much cap problems in
60's turntables as in today's motheroards But 40 years may be too
much for some of them..

If the motor runs on dc, and mechanics naturally have more "resistance"
on the point where it jams, it increases the load and the ripple
voltage increases on that point, and the motor doesn't get enough
effective voltage to work.

This is, however, just a kind of hypothesis, and actually an unlikely
reason if there isn't other symptoms (e.g. humming noise on output etc.)

 

[Sam Goldwasser]

Could be wires bound up underneath or bad tonearm bearing(s)...


Mark Z.

I think Sam and a couple of others nailed it. Grease drys up and
makes things bind. The lever which trips the 'rejuct' mech' on those
old changers is definitely suspect; but I imagine the rest of the guts
are just as gummy.

For a novice, these are not the easiest things to work on. The timing
of the cams is similar in some ways to a VCR. Get it wrong upon
reassembly, and it won't work.

Just don't disasemble beyond removing the platter. Most of the other
stuff can be cleaned in-place.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Michael Kennedy]

Mechanical problem is very likely, but if not, then I would guess dried

out electrolytic caps.

What? If this were an electronic problem I'd understand thinking it was a
cap but this problem is totally mechanical.

If the motor runs on dc, and mechanics naturally have more "resistance"
on the point where it jams, it increases the load and the ripple
voltage increases on that point, and the motor doesn't get enough
effective voltage to work.

I'm guessing you've never played with a turntable. There isn't a motor
guiding the needle. The turntable turns and the resistance of the grooves in
the record guide the needle inward. I'd have to agree with everyone else in
saying that this is probably dried out grease or a mechanical failure.

- Mike

 

[Dave Plowman (News)]

I'm guessing you've never played with a turntable. There isn't a motor
guiding the needle.

There were a few which had parallel tracking motor driven pickups. B&O and
Revox, to name but two.

 

[Chuck]

alright i have a very old turntable that was probably made in the late
1960s. whenever i play a record the needle always stops moving on the
record, usually in the middle of the last song. i have tried other
records but it always stops in the same place. it feels like there is a
spring mechanism that keeps it from moving in all the way in. so my
question is what is causing this to happen, and how can i fix it. just
please dont tell me to buy one of these new ones.

If you post the name and model number of the turntable, I should be
able to send you a step by step repair procedure. Chuck

 

[David Nebenzahl]

Dave Plowman (News) spake thus:

There were a few which had parallel tracking motor driven pickups. B&O and
Revox, to name but two.

As the O.P. said this was a turntable from the 1960s, it is undoubtedly
a simple mechanical device, with a synchronous induction motor with no
associated electronics, and certainly no servo-operated tonearm. I'd be
willing bet money on it.

The previous poster's (or a couple back) speculation was only that.


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"

 

[Dave Plowman (News)]

As the O.P. said this was a turntable from the 1960s, it is undoubtedly
a simple mechanical device, with a synchronous induction motor with no
associated electronics, and certainly no servo-operated tonearm. I'd be
willing bet money on it.

Oh I'd agree.

The previous poster's (or a couple back) speculation was only that.

Well, yes. But where would newsgroups be without pedantry?

 

[Michael Kennedy]

Well, yes. But where would newsgroups be without pedantry?

Very True...

- Mike