Seeburg SMC1 / Disco flutter sound

This problem has been solved.

Main problem was a hardened motor coupling. Having never held a new one in my hand the old one felt flexible. But it was clearly not.
2nd part of the problem was the thrust-bearing over the motor, it was too tight. But this only caused a light flutter.

Thanks for all the help!

I'm still not happy with the sound on this Juke. However, I have never heard one play so maybe I'm just asking too much?

Main problem is that there is still a light flutter in the sound. You can hear this best on a constant tone in the mid-range. Disco songs, beats etc sound marvelous. I'm a little at a loss here. Here is a list of findings :

1. It seems worse sometimes on the same record
2. Motor vibrates a lot (Japanese motor), though I never felt others so I have no reference. But It's a lot
3. Not sure about needle pressure, can the springs become weak? They are now set at max, with spring still in the lower hole.
4. I checked and double checked the bearings, seems fine to me, when the bearing above the motor coupler is too tight it gives a heavy flutter sound.
5. There are new rubber pad under the motor, new motor coupler and new motor mounts placed

I must be missing something, could the Motor-run cap be at fault?

Hi William,
Mechanically, here s a list of what can cause that, on any model--
1."Frozen" ball bearings inside the turntable.
2. Turntable thrust bearing ball worn out ( flat/"sticking"), or mal-adjusted.
3. Clutch thrust bearing too tight, or, loose.
4.Top of motor shaft thrust bearing mal-adjusted, or motor coupling "hard", or, incorrectly installed.
5. Any other "rubber parts" hard.
6. Needle pressure too tight, or, if using "aftermarket needles", too loose--
7. Suspension nuts not run up all the way, and studs not free of base frame.
Electrically--
1. Motor cap second section contacts failing to open during play.
On SMC models ONLY--
Non-updated interface board in the PCC. ( which one is installed in your phono ?)
On all models--
A "poorly making" contact (point, or plug), in the motor circuit.
EDIT--One other reason this may happen on the model STD-3* is that when the newly re-designed suspension was used in the first production runs, of this model, it was found that there was an error in design. They quickly changed this, and issued "update" kits, free of charge to their distribs. If the phono was "legally" purchased, and the distrib did his job, all purchasers of that model were informed of this problem, and could request a kit for each phono, so affected. This "kit" consisted of four rubber "cones" that were to replace the four "flat rubbers" that were formerly inserted inside of the suspension springs( see "art work" in mech parts books).
* I have seen ONE, STD-4, with this same problem, but it is my guess that "somebody" changed the suspension system in this cabinet ? It's sure possible that the same thing could have been done on a SMC---

Ron Rich

This problem is still ongoing and is taking the joy out of listening to the music.
I'll buy your Mech book and see if I missed anything during my hours of inspection and testing.

Hope I can resolve this issue.

Hi William,
Upon re-reading all posts two things stand out--( along with my stupid error on the cap switches !)
1. You say you "replaced" the rubber motor mount--where did you find some to fit that motor ?
2. You say that there is no "up-down play" in the motor shaft. How did you determine this ? That adjustment MUST be done as per the manual, with the motor coupler detached. Then the motor coupler should be connected to the top shaft first, then a SLIGHT upward pressure added to it, as it's tightened onto the motor. BTW--what condition is the motor support plug, in ?
Ron Rich

Hi Ron,

Very happy with your input still on this, let me try to answer your questions.

1. I assume you mean that the inner dimensions of the mounts are different from the older mounts available. The product I bought is this one. It's a special version with an adapter ring so it fits.
2. I did the adjustment , I think, following some internet link. I cannot vouch for it being done exactly as your manual says as I do not have that yet. It's ordered though so that will be checked soon.
3. The motor support (the rubber under the motor) is also new, I bought this one

The coupler I bought is this one

I also replaced the turntable rubbers with these ones

Hi William,
IMHO, buying parts from Musikboxen", you will ALWAYS get high quality, correct replacement parts ! They are great people !
(Well, Hildegard is a great person--not 100 % sure about Oliver ?? )
The coupler "adjustment" should be checked also, are ALL thrust bearing (balls) adjusted properly, and are they all "free", and good ?
Might try one thing--play a record that gives problems, and hold the clamp arm tighter onto the record with your hand. If that cures the problem, your clamp arm spring has been "over stretched", and will need to be replaced.
Other then that--is the record "touching" or "rubbing" on something ( record ramp, record rack separators, record lift arm, needle brush assembly) ?? I once saw one doing that where someone had run a cable across the mechanism for the PRVC--it was sitting just far enough over the record rack, that the top of SOME records just touched it, while playing--
Ron Rich

Hi Ron,

Good to hear te parts are good.

I took the motor out and noticed some "play" in the "drive shaft"? The one where the motor coupling is connected to.

Here is a video of it: play on driveshaft

The Clamp is holding a firm grip. No change when pressing extra against it. When I play without the recordrack mounted the problem is still there. So the record is not touching anything.

Hi William,
I dono--I have never attempted to check "side play" on one before --but it would seem that you have quite a bit there---
I think that might be overcome, if the motor coupler is correctly installed ??
Did you check ALL ball bearings ? Especially the turntable thrust ?
Ron Rich

I have not yet taken apart the turntable completely. I did take it apart a little to mount the new turntable rubbers. The bearings felt good.

I believe there is nothing left to do but take the whole turntable out of it and see how everything is.
We will make a new bearing then from brass and fix that play.

could you tell meif the motor should vibrate much? It feels as if it's a lot. When the power is taken off the motor it's very smooth.

Well, off to take the mech out now and off to my dads. He's the mech guy of the family:)

William,
There should be no motor vibration, when the mechanism is in "play position"---. Ron Rich

I have a situation now where the jukebox sounds great! Very happy with that.
When I took it all apart I noticed that the new motor=mount that I got was a lot stiffer than the Original one still mounted at the bottom. So I removed the top mount and put the motor back in without it.
Problem solved (I keep the motor in place with my hand during testing).

This makes me believe that the rubber is not absorbing the vibrations enough. Or, My motor is vibrating too much.

You say that in play position I should feel no vibration. I definately feel that the motor is running when touching it in play position.

Hi William,
Not being able to "feel it" puts me at a dis-advantage--and I don't have a NIDEC motor in my SMC- so I really can't compare--but I think you should be able to "feel it run", however motor should not have excessive vibrations --the coupler should absorb the vibrations, if PROPERLY installed.
Did you change both motor mounts, or only one ?
Ron Rich

I replaced only one, the top one. The one at the bottom looks fine still, thought the rubber is a lot softer.

Strange,
I find that the lower one is the one that fails first on that type motor-I think that I would change both of them--and, BTW, they must be tight on the motor--shim, or glue the new ones on, if needed. BE SURE motor is oiled with ONLY 20 wt. motor oil--these motors are prone to sizing, if not properly oiled ( about 98% less likely to happen, if using my new "Gen 2 MCU", as we added a motor protection timer to it). Ron Rich