help Technics SL-23 won't stop spinning!

turning japanese
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tjcombo
Posts: 3
Joined: 31 Dec 2012 01:12

help Technics SL-23 won't stop spinning!

Post by tjcombo » 14 Mar 2019 19:24

Hi guys,
My Technics Sl-23 was running fine(ish) until today, when I finally wanted to get rid of a problem where the tonearm wouldn't go back to its resting position after finishing the record. In the manual I saw that I could turn the auto return adjustment screw, but since the screw did not quite align with the hole, I decided to open up the TT to see if there was something I did wrong the last time I did maintenance (cleaning the infamous speed pitch knobs.

Then, I messed up: after taking off the spindle and the belt, I manually turned the mechanism a few times, then turned the turntable over to see if I could get at the misaligned screw like that. After closing the turntable back up and trying unsuccessfully to adjust the auto return adjustment screw, everything went haywire.
I've taken a short video below to demonstrate the problem:

As you can see, the turntable is already running while the tonearm is in its resting position. I encounter considerable resistance when I put the arm over the record and the 'clunking' sound is immediately audible when I release the arm, after which it immediately goes back to its resting position (after which the turntable continues to spin).

I've taken a few shots of the innards to show off where I think the problem might be:
https://i.imgur.com/cuyPBrt.jpg
https://i.imgur.com/5Fbaot8.jpg
Invisible in the first picture and visible in the second picture is a little plastic lever that moves progressively towards the right when the turntable is finishing its cycle. In the utmost right position is the 'resting' position I mentioned earlier. I think it's where the issue lies and I also think it shouldn't be all the way over to the left when I leave it unattended.

https://i.imgur.com/TpNyNg2.jpg
And then, a shot from the inside. My problem is that I can't really tell in which position the mechanism is supposed to be and I have no way of telling what I've exactly done wrong and how I should go about fixing it.

I'm sorry for the rather vague description: I'm a bit of a newbie when it comes to repair, although I have a lot of good will :D Anyone out there who has seen similar problems or has more than a passing acquintance of SL-23 decks to tell me which stupid mistake I've made? I think (rather hope) that the issue is easy to fix, but I might be entirely wrong.
TIA!!

musicmn
long player
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Re: help Technics SL-23 won't stop spinning!

Post by musicmn » 15 Mar 2019 01:55

Hi TJ, I've worked on a lot of those turntables but I don't have any pictures I can use to help you out. But I'll try to explain what I see. When the tonearm is in the rest stand that little plastic piece in your second pic that you are touching should be all the way to the right. As the tonearm moves across a record that lever moves with it. When the needle is in the lead out grove that plastic piece pushes on the trip pawls that are on the main cam gear. The trip pawls are then engaged by the tab on the spindle gear and that's what starts the return of the tonearm to the rest stand. If that plastic part is under the cam wheel when the tonearm is in the rest stand then somehow it got out of position. In your last pic You can see that white long lever, under that cover on that lever is a small ball bearing. I would remove that cover and check to see if the ball bearing still there and that it is riding in the groove on the lever. Hope fully the ball bearing is still there and just stuck in between the lever and the cover. If the ball bearing was just stuck before you assemble it clean the ball bearing the groove in the lever and inside the cover with a rag and alcohol. Do not use grease on anything in this area it's not needed. The reason the tonearm was not returning to the rest stand at the end of a record could be that the trip pawls on the cam wheel are dirty from old grease. The trip pawls are the silver parts on the cam wheel they need to move freely. When they have old grease on them the tonearm moving across a record can't over come the old grease and move them into position. The easiest way to clean them is to slip a thin rag dipped in alcohol in between them and under them where they ride on the cam wheel. Do this until you see no old grease on the rag and they are moving freely. If you have some very thin grease and a small brush you can apply just a little grease under trip pawls and in between them. Or you can just leave them dry they do work either way. I hope something here helps.

tjcombo
Posts: 3
Joined: 31 Dec 2012 01:12

Re: help Technics SL-23 won't stop spinning!

Post by tjcombo » 15 Mar 2019 13:15

Hey musicmn,
Thanks ever so much for all that useful information!! I'm going to supply as much information (with video and pictures) and hopefully I'll figure out what the hell I'm doing wrong.
In your last pic You can see that white long lever, under that cover on that lever is a small ball bearing. I would remove that cover and check to see if the ball bearing still there and that it is riding in the groove on the lever.
https://i.imgur.com/Lw42lx8.jpg
(blue arrow) As requested, I checked if the ball bearing was present and clean. It was still there and for good measure I've cleaned it with a q-tip. Now, if I'm assuming correctly, the ball bearing should ride along the plastic groove you mentioned inside of the plastic casing (blue arrow). If the ball bearing is present and the groove intact, I'm guessing that's not where the problem is coming from.

(green arrow) The problems started when I adjusted the screw marked with the green arrow in the top left corner. From what I can tell, this is a positioning screw to adjust the position of the small white lever that holds the black plastic platform in place in the resting position. I've tried adjusting this screw in several different positions, but it may well be that during my attempts I've been actually loosening or tightening that screw with disastrous effects. I have no way of telling, so it'd be much appreciated if you could tell me what this screw actually does.

Finally, I've taken a video that shows me rotating the main turntable wheel to demonstrate what happens when I fully rotate the main cog. Hopefully you can see how the mechanism slips out of place.



I've been at this for a few hours, but I can't seem to figure out what's going wrong. I would absolutely love some input. It's probably something I'm not thinking of right now. I sincerely hope I haven't made any irrepairable mistake during the process.

Alec124c41
vinyl engineer
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Canada
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Re: help Technics SL-23 won't stop spinning!

Post by Alec124c41 » 24 Mar 2019 14:12

Look at that screw with the green arrow. How does it work? Is the sloped end of that lever supposed to be limited by the flange of the top of the screw?

Cheers,
Alec

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