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Beogram 8002 sticking tonearm

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etype76
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etype76 posted on Wed, Sep 21 2016 11:59 AM

Hi,

I acquired a Beogram 8002 in March this year. The unit I got is near mint and has had its caps replaced. The issue I've been having with it has been occurring since I got it out of the original box. I've been thinking it was the servo-belt being incorrect, but now I'm not sure. Here's the issue:

When I hit PLAY, often, the tonearm doesn't come out. The platter rotates at 33.33. I manually give the brass worm drive a turn by hand reaching towards the back of the unit and then everything is fine. It will play a side, or two or even a few records but then the arm will be stuck in it's resting place until I 'nudge' the worm drive again. I've changed the belt twice now. First change was to swap the one that came with it (non-original) with another that the seller sent to me. This was a slightly softer rubber and seemed to fit nicely. The second, was Martin's triangular profile belt. But I'm still having issues with the tonearm which now leads me to conclude that it can not be the belt here. One point, There is some silicone type rubber on the end of both the silver guide rails. I guess to prevent them popping out on shipment across the world and maybe to dampen any vibrations. I'm now thinking that the underside of the tonearm assembly could be catching on this silicone. 

I really want to get to the bottom of this, I'm sure it's something mechanical. 

Does anyone have any suggestions? 

 

 

 

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Dillen
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Dillen replied on Wed, Sep 21 2016 3:13 PM

There should be no silicone anywhere.
Photo please ?

Martin

sonavor
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Hi,

One of my Beogram 8002 turntables started displaying similar behavior earlier this year. I haven't had any time to work on it but the symptoms are: Platter turns on Play but the tonearm doesn't move. When the problem first appeared it was intermittent where it would eventually start working. Now it won't move at all. I was also thinking it is something mechanical.

What happens when you disconnect the belt? Does the tonearm motor always spin when Play is pressed? I wonder if the tonearm motor could be failing? When I get the turntable to my bench I will try swapping the tonearm motor with a spare. If the motor is the problem it might be able to be repaired.

I have another Beogram 8002 turntable with different problem. Occasionally it will start when Play was pressed but the tonearm will just travel (without setting down) to the end and stop. It won't return. I have temporarily fixed that problem by reseating the ribbon cable that goes from the control panel to the main board. I probably need to replace that cable and board connector as the issue comes back once in a while. I might swap tonearm motors between these two turntables and see what happens.

-sonavor

etype76
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Not sure if the motor still runs with the belt off. There's certainly some resistance when I turn the worm drive a bit to get the tonearm to move out. After that, it runs very smoothly. 

 

Here's a pic of the situation. There's the rubber like stuff on the ends of the guide rails. I've removed bits of that but not all. 

 

 


sonavor
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The rubber ends on the guide rail is to dampen vibration. I will try to clear some space and get my Beogram 8002 that has the same problem to my workbench and open it up tonight. Your post reminded me of the problem and I am curious now to resolve it.

-sonavor

Dillen
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Dillen replied on Wed, Sep 21 2016 4:54 PM

That rubber/silicone stuff is not original.
Perhaps the holding clips for the rails broke at some point? I cannot tell from the photo if they are intact.

Martin

sonavor
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From your picture it all I see is a glob of silicone-like grease on the end of the rails. Those rails don't turn so that grease wouldn't be necessary. Like Martin suggested, maybe there is a problem with the rail guides/clips that the tonearm assembly rides (on the rails).
I dug up an old picture of one of my Beogram 8002 that shows the two rails and the drive shaft disassembled. The US version of the BG8002 has that rubber dampener on the ends of the rear rail.

I still want to know (when the problem occurs) if the motor is trying to operate but is blocked or whether the motor is not trying to drive.


etype76
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I went back inside this morning. Sonavor, I pressed play while the belt was off and the motor ran strongly ten straight times in a row and always seems to spin with the belt on. I decided to completely clean up the rails without actually removing them. That stuff on the ends is not grease, more silicone/rubber. I got it off both rails. All clips look in tact. I cleaned up the rails and applied some oil. Now, I've been here before so I don't want to seem overconfident but things seem to be working as they should. I.e, the tonearm comes out every time I press PLAY. Obviously, the issue with your 8002 is likely something else...

 

It might revert back to sticking but fingers crossed. 

 

Here's how it looks now:

 

 

 

 


sonavor
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I got my Beogram readjusted to where it is working again as well. The problem was a mechanical adjustment issue.
This picture is of the Beogram 8002 before the fix. The problem is that when the tonearm returns to rest via the Stop button or automatic return at the end of playing a record, the stop switch isn't immediately stopping the tonearm assembly. There is a little delay and the tonearm assembly travels too far towards the motor. It travels so far that the left side of the tonearm assembly actually raises up a bit.


sonavor
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With the left side of the tonearm assembly raised up enough, the tonearm won't be able to make good enough contact with the drive shaft and the tonearm won't start (when Play is pressed).

I noticed that the switch does engage earlier than where the tonearm assembly is finally stopping. When I use the reverse arm movement button on the control panel to return the tonearm to the start position, the tonearm assembly stops way sooner that when the automatic return is in control.
Here is where the tonearm assembly stops when manually returning the arm to the start position. You can see the gap between the tonearm assembly and the motor is much greater. At this position the tonearm assembly remains level at the stopping point.


sonavor
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Normally to adjust the tonearm stopping point and set down point is just to loosen the screw for the stop switch assembly and rotating the position a little. In this case, the set down point was right where it needed to be but the stopping point was too late in halting the tonearm assembly. To try and make a decent compromise of the adjustment I put down a small label and put a few markings to help me adjust the lever of the switch. I ended up rotating the switch down a little and also bending the switch lever. The final adjustment was where the switch off position is as shown in the following picture. This is when the tonearm has moved to the set down position. The stop (at rest) position is where the red mark is. With this adjustment the tonearm assembly is returning to the start position and stopping without any rise in the tonearm assembly from the rails. The set down point for this adjustment is a little closer to the first track grooves than I would like but it is dropping down prior to the music grooves.


sonavor
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Here is where the tonearm assembly rest position is now that I have made the adjustments. The manual return of the tonearm also stops here so I can start using this Beogram again.
Martin, please let me know if there is another option in this adjustment I have missed. Perhaps changing out the switch would give me more control over the stop and set down position.
In case anyone is wondering, rotating the switch assembly upwards made it where I couldn't adjust the set down of the tonearm before the first music grooves.


etype76
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Very informative pics as always! My tonearm assembly has stuck once since which likely means it will happen again but it is definitely much better. I also thought that perhaps the tonearm was travelling a bit too far at rest. There is a tiny but noticeable 'wobble' when it comes to a rest which may indicate that it is raising up a bit. Anyway, I will see it the current setup works over the weekend. I did adjust that SO switch slightly and could see that the set down point was altered but it didn't seem to make a difference to the stopping point of the tonearm assembly. I would have thought moving the switch downwards would lead to it stopping later rather than sooner, so maybe your adjustment of the lever compensated that. 

 

Cheers

 

 

sonavor
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The wobble of the tonearm assembly is what my problem was. The assembly was lifting up quite a bit at rest. I initially moved the switch upwards to move the engagment of the switch sooner and that did remedy the stopping point problem. However, that meant the disengaging of the switch happens later and the set down position happens too late. I didn't want to bend the arm back the other direction to fix that case but I suppose I could have reached the same result if I had. So I moved the switch downward and made the adjustment that way.

I will have to make it a point to check for that tonearm rest position wobble when I restore those turntables. Out of my four working BG8002 turntables, two don't have any wobble, this third one had the problem I mentioned above and the fourth one has a very slight wobble. I also checked my BG8000 and it doesn't have any wobble. Maybe the problem is with the switch. While the Beogram is still on the bench I might swap out the switch from some backlog Beograms. I have several waiting to be repaired so the exchange would be pretty easy. 

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