Sl-1650 Tone Arm Problem

turning japanese
vinylbluegrass
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SL-1650 Tone Arm Problem

Post by vinylbluegrass » 18 Jan 2011 20:25

The tone arm on my 1650 (automatic) won't cycle properly. When I cycle the arm it lifts, swings to the end of the album, then swings back to the start, and shuts off. In other words, the auto function doesn't auto correctly.

Am able to use manually.

Haven't been inside the thing. Could it be old, hard grease? What else?

All suggestions appreciated.

Thanks.....

VinylIsTheBest
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Post by VinylIsTheBest » 20 Jan 2011 03:56

I have a SL-1650 also. It seems to me that your auto set-down adjustment is way off. In the manual it shows you how to adjust the set-down.

https://www.vinylengine.com/library/tec ... 1650.shtml

Regards.

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Post by Brick » 20 Jan 2011 07:20

I am having this exact same issue with a 1600 mk1. Adjusting the start and stop screws doesn't make much difference on mine. It picks up fine in manual play, tho

vinylbluegrass
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Post by vinylbluegrass » 20 Jan 2011 16:13

VinylIsTheBest..... Do you mean the automatic start and automatic return positions adjustments?

Thanks for the reply....

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Post by VinylIsTheBest » 22 Jan 2011 21:50

vinylbluegrass wrote:VinylIsTheBest..... Do you mean the automatic start and automatic return positions adjustments?

Thanks for the reply....

Yes. The one under the platter and the other one on the arm base.

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Post by Brick » 22 Jan 2011 21:56

Spent a couple hours cleaning the 1600 up, got all the grease out and replaced, and finally figured out what I think is causing the problem with the arm drop location, but not how to fix it. If anyone has a working one apart or experience with this I'd love to hear about it.

The way I have come to understand (through trial and error, so I may be missing something) the arm drop and its location is this: The metal plate the adjustment screw is on rotates with the arm until it makes contact with the plastic arm that is set by the "size" switch on the turntable faceplate. This 3 step plate stops the arm rotation at its specified point while the rest of the auto mechanism goes through an entire cycle, and the arm drops there. It then moves slightly to allow the arm to freely travel across the record.

What has happened inside mine is that the 3 stepped arm moves past its smallest step, and the arm gets dragged through the entire cycle because it never contacts one of the steps. What i haven't been able to figure out, is how the record size switch engages this arm or how the stepped arm is put back into position.

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Post by Brick » 23 Jan 2011 18:41

I found this video via Audiokarma that shows the cuing issue. You only have to watch the first bit to see it, the rest is pitch related.

http://www.youtube.com/watch?v=kYMKpB3oq2I

And I figured out the problem this morning, mine is working as it is supposed to!

I'll try to post pics later, but, as I thought, the problem was in the record size arm. The pivot bearing for the arm was seized onto the post, but the plastic arm was still rotating because the auto system forced it to spin on the bearing when it couldn't on the post. The little follower spring didn't have enough strength to pull it back around and it became stuck in "no record size" position, which caused the problem.

I knew that arm felt very tight, but couldn't figure out how to get it off to lube it. This morning I soaked it in alcohol, working it back and forth and realized the center bushing was not moving. I soaked it some more, and then decided to exert a little more pressure on it than I was comfortable with. I stuck a screwdriver blade under it as far as I could and twisted it. With some pressure, the entire arm moved upwards, and I could work it off the post.

Cleaned it, lubed it up and reinstalled it. Works as original. To say I am pleased is an understatement.

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Post by Brick » 28 Jan 2011 03:09

Wanted to get back to post pics (sorry for the quality) and try to explain it better. I don't know how to get pics to show up in the post so I'll settle for links.

16245

I've removed the tonearm to get at everything.

This is the position the arm was getting stuck in. This arm has three stop points on it above the yellow arrow which select record size during auto play. It is engaged by the selector switch on the face plate pushing the long arm that extends towards the bottom of the picture.

The auto function rotates this arm as part of its cycle to allow it to reset if a change in size selection has occurred, and a follower spring returns it to rest so the tonearm can engage it and set down at the beginning of the record. The bushing on this arm is pointed at by the blue arrow, and on my table had seize to the post. Because the auto function is very strong, when it tries to cycle with the bushing seized, it breaks the plastic loose from the bushing and forces it to turn around the bushing instead of the post. The follower spring has no chance of pulling the arm back to rest because the plastic is very tight to the bushing, so it stays at the extreme range of its travel.

When the auto system fails to make contact with the stops on the selector arm, it moves the arm all the way to the spindle before setting down, by which time the auto return is already trying to retrieve the arm.

16246

This is where the arm should return to. I have put a screwdriver in the picture to show the spot I pried from to force the arm off its post so I could lube it. The arrow is where I pried. I had to partially cycle the auto mechanism to get clearance to get the screwdriver in there, which I did by turning the spindle by hand with the system engaged. Once I got the arm pried off, I cleaned everything really well with alcohol and then lubed it with lithium grease.

Put everything back together and it cycles and functions like it was designed to.

Hope this helps someone else as much as the article on cueing issues has helped me.

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Re: Sl-1650 Tone Arm Problem

Post by sichejo » 15 Dec 2011 07:48

Thanks for the info. I bought a 1650 that would swing over to the end of the record. Your pictures helped me get it straightened out. The lever was not seized on mine, the grease was starting to get hard. I cleaned the post, and greased everything else that was a moving part. Works great now!

This is the first non MK2 TT I have worked on. The 1600MK2 definitely has a smoother action during the arm moving process. Probably helps to the separate motor driving the mechanism.

John

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Re: Sl-1650 Tone Arm Problem

Post by sichejo » 15 Dec 2011 14:59

I should have said "Probably helps to the have a separate motor driving the mechanism."

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Re: Sl-1650 Tone Arm Problem

Post by Brick » 15 Dec 2011 15:08

I actually like the mechanical movement better, doesn't seem like a robot, I guess :D

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Re: Sl-1650 Tone Arm Problem

Post by sichejo » 16 Dec 2011 02:12

On your 1600, are the speed controls real sensitive? I have cleaned all 4 pots, they are really hard to get set correctly (and stay). I am wondering if I have a problem in the speed control circuit.

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Re: Sl-1650 Tone Arm Problem

Post by Brick » 16 Dec 2011 05:14

I'd try cleaning them again. Make sure you get the Deoxit in them good, and work them one end to the other a bunch of times. Some take a while to clean up.

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Re: Sl-1650 Tone Arm Problem

Post by eddie edirol » 24 Dec 2011 23:06

sichejo wrote:On your 1600, are the speed controls real sensitive? I have cleaned all 4 pots, they are really hard to get set correctly (and stay). I am wondering if I have a problem in the speed control circuit.
Did you unsolder the pot and take it apart? If the speed problem is that bad, then you need to take it apart to get the contacts back in touch with each other. Have to be very delicate though, not an operation for the heavy handed. Ive had to do the same thing with 3 technics decks, and this always fixes the pitch issues.

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Re: Sl-1650 Tone Arm Problem

Post by Nurb » 10 Aug 2012 18:54

Sorry to revive this thread, but I just purchased a SL-1650 for $10 at a garage sale and I am having the same problem with the tone arm not starting in the correct spot, and the adjustment screws doing nothing. Any chance I could get some help or revived pictures?

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