Help needed, Beogram 6006

[YannChris]

Hello Beoworlders,

The belt of the arm carriage of my Beogram 6006 (type 5625, 1984,  with linear motor) was broken and I replaced it.

Unfortunately, the detection arm was damaged during the disassembly  and I had to fix it by gluing the plastic holder where the arm is screwed on the carriage.

I managed to have it horizontal.

Now, when I play a record, the carriage moves to the beginning of the record (it also makes a complete cycle with speed change if no record is present) and the stylus descends. So it seems that the detection system is OK.

But when the disc reading starts, the arm does not move and the stylus jumps as if with a scratched disc (see attahed video). Same problem if I move the arm in the middle of the record.

What could it be and what can I check?

Thanks by advance,

Yann.

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[YannChris]

A little up.

I tried to adjust the tracking arm’s height at 19,5mm as explained in the service manual.

I noticed that a small tap on the tracking arm starts the playback, as if there is a focus issue with the sensor.

What could I do to go further?

Kind regards,

Yann.

Location: Brittany, France

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[Mark-sf]

It appears that the arm is being blocked from moving inward once it lowers. I would check with it open and lowering the arm to the right of the platter. It should move freely the 1/2 inch to the sensor arm. Sometimes the optical shutter is sticking or has be rotated so it hits its stop prematurely.

[YannChris]

Hi Mark,

Thanks for your reply.

I’ve ordered a new belt from Beoparts and await for it.

I’ll take back the TT to the bench when I’ll recieve it and let you know.

Kind regards,

Yann.

Location: Brittany, France

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[YannChris]

Hi,

Attached a new video with the issue and what happens when I tap slightly the chassis.

You can also note the carriage motor on the right of the video.

It stops moving at 13′ of the video and goes back after the tap. First rather fast, then by steps following the move of the reading arm.

Same issue with my 3 cartidges, so I doubt that the stylus are involved.

Tracking arm set at 19,5 mm from the aluminium part of the platter and tracking weight at 1,2 g.

So I wonder if something is mis-aligned in the carriage, but I don’t know how to remove it from the rails and would avoid to break anything.

May someone explain the process?

Kind regards,

Yann.

 

 

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[Mark-sf]

You need to adjust the aperture (B) so that the arm moves every 2 revolutions. Make sure that stray light does not leak in when doing it.

[YannChris]

Thank you Mark,

I’ll try to make the adjustment, it seems to be rather tricky.

 

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[YannChris]

Hi Mark,

I’m rather worried to touch this setting.

First the screw is not easy to reach, second it has never been touched since factory and everything was OK until my desastrous attempt to bring the turntable to service position: I forgot to push the chassis to the right and of course, the arms suffered:

• The detection arm broke. I glued it and I think that the problem is solved as the beginning and the end of the disk are detected.
• I did not notice anything on the reading arm, but obviously something went wrong.

Here are the checks and settings already done:

• The platter is flush with the aluminium panel,
• The arms are 23 mm to the aluminium part of the platter,
• Tracking force is 1,2 g, measured with an electronic gauge.

In some cases, the reading of the disk from the beginning works well and if I do not cue to another song it goes to the end without difficulty. In other cases not.

I already posted a video showing that “tapping” on the chassis makes the arm move again. Today I noticed that blowing a bit hard near the cartridge has the same effect.

The end of the disk is more problematic. I noticed that when the grooves of the disk are more widely spaced, the cantilever goes far to the left but the arm does not move, so the stylus skips… until I blow. Then the arm moves again, first to the center, then back to parking position.

Could it be something in the lowering of the arm which in some cases does not go down far enough? And what could I check?

Kind regards,

Yann.

 

 

Location: Brittany, France

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[Mark-sf]

I would check that if you manually lower the arm before the edge of the record that it goes down to just above the top plate. I would also check the tracking force calibration.

[YannChris]

Hi Mark,

Some progress in understanding following your last suggestions.

First I observed the lowering of the arm (“Descent” video, sorry for the quality). I seems to descend deep enough.

Then I checked the tracking force with an electronic gauge (bought new for the testings) and noticed some oddities:

• After the arm has finished it’s lowering, the tracking force is not sufficient. But if I give a little tap on the turntable, the tracking force meets the required one (“tracking force” video).
• At the end of a disc with spaced grooves, the arm skips. But if I blow strongly on the arm, it moves again to the end and goes in parking position (blow video).
• If I blow or tap at the beginnig of this disk, the arm does not skip on spaced grooves.

Could there be something that ‘holds back’ the arm during its descent, preventing it from pressing on the disc with the correct tracking force?

Blowing on the arm at the beginning of each disc is not a very beo-ish and practical practice!!

Kind regards,

Yann

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[Mark-sf]

I would set the tracking force to zero, remove the arm cover and ensure the arm floats with no friction up to down. If it doesn’t you have found your issue and need to find where it is binding. Sometimes its the cover, tonearm wires too tight, sticky bearing, etc.

[YannChris]

Hi Mark,

I unmounted the carriage to check it one more time.

A the rear of the assembly, the voice coil seems to be connected to a metallic pin which slides in a sort of screw that you can see on the picture.

The rear party of the pin seemed to move to the side and touch the plastic support of the detection arm.

After centering the pin, the problem seems to be partially solved, as LPs are correctly read.

I said partially because small 45 rpm discs still skips. As I rarely listen to these, I will not go further until there is a problem with LPs.

Thanks for your help and useful tips.

Kind regards,

Yann.

 

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