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Beogram 4004 problem

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riis
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riis posted on Fri, Feb 5 2016 1:00 PM

I have a Beogram 4004 which I haven't used for many years. I took it out of storage the other day and tried to get it going. The tone arm didn't lower, but after cleaning and lubricating and giving the solenoid a little "massage" it worked almost perfectly.

The problem is that the arm doesn't always raise as it should on return. Sometimes it works ok but sometimes the arm doesn't raise before it has travelled 1-2 cm on return.

/riis

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riis
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riis replied on Fri, Feb 5 2016 8:07 PM

I also unscrewed the three leveling bolts and took out the height adjustment bolt. I put it back without paying much attention to the level. 

Can this have caused the problem?

Søren Mexico
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Your problem is probably the damper blue arrow in the pic, dismantle it for cleaning and lubricating, Here one thread and here another to study, it is important that the whole mechanism is clean, lubricated and everything moves freely

Collecting Vintage B&O is not a hobby, its a lifestyle.

sonavor
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Hi,

Are you saying that when you press the raise tonearm button or the stop button there is a time delay before the Beogram responds and the tonearm raises up? If that is the case then it could require a capacitor kit from Dillen. However, first check the tonearm raise/lower lever. It is attached to the fixed detector arm and fits in the V shaped notch at the rear of the tonearm assembly. When the solenoid activates and pushes that lever, it releases the tonearm. That lever can often start sticking in its pivot point where the lever doesn't move easily. That would cause problems with the arm raising if the lever doesn't pull back down when the solenoid releases. Removing and cleaning that lever pivot is not too difficult but requires quite a bit of disassembly. Checkout this thread and this blog.

The bolts you took out are for leveling the platter and setting its height with respect to the tonearm. Unless you are going to go through all of the service manual adjustments I wouldn't mess with that just yet. I can't seeing that affecting your tonearm raising problem.

-sonavor

Søren Mexico
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Here the raise lower lever

Collecting Vintage B&O is not a hobby, its a lifestyle.

riis
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riis replied on Fri, Feb 5 2016 8:51 PM

No there is no delay when I press the raise tonearm button or the stop button. These functions work ok. The problem sometimes (and only sometimes) occurs when the record is finished playing and the tonearm returns.

riis
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riis replied on Fri, Feb 5 2016 8:55 PM

Søren thanks for the pictures. Do you mean that I should lubricate the areas marked with blue and red arrows?

sonavor
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riis:

No there is no delay when I press the raise tonearm button or the stop button. These functions work ok. The problem sometimes (and only sometimes) occurs when the record is finished playing and the tonearm returns.

Okay, so what you are saying is that there is a problem detecting the end of the record and raising up?

riis
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riis replied on Fri, Feb 5 2016 9:19 PM

Yes, that's the problem.

riis
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riis replied on Fri, Feb 5 2016 9:19 PM

Yes, that's the problem.

sonavor
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riis:

Yes, that's the problem.

That is a different issue then. I would say your mechanical linkage is all fine if the normal raise and lowering works via the cueing buttons.

With the end of record detection, does it eventually raise automatically...meaning is the problem just that it isn't detecting the stop point where you expect it? Or does it never raise up by itself at the end?

Those model Beogram 400x turntables use a plastic scale with black markings to trigger the turntable's tonearm position events. The markings affect a light source to a photo resistor. If the problem is electrical then I would still look at replacing the electrolytic capacitors. If it is a mechanical problem with the scale (and its travel) you would need to observe the tonearm carriage travel with the Beogram opened up to see what is going on. Maybe measure the signals being generated for those events.

-sonavor

riis
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riis replied on Fri, Feb 5 2016 9:54 PM

I understand what you mean, but there is no pattern in the way the tonearn returns. Worst case is that the arm returns to stop without raising. Not very good for record nor stylus. A little better is when the arm raises after travelling one or two cm and then returns to stop. And then there are times where it just works perfectly

I hope you understand what I mean.

sonavor
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riis:

I understand what you mean, but there is no pattern in the way the tonearn returns. Worst case is that the arm returns to stop without raising. Not very good for record nor stylus. A little better is when the arm raises after travelling one or two cm and then returns to stop. And then there are times where it just works perfectly

I hope you understand what I mean.

I thinks so. If the other tonearm positions are being detected correctly by the photoresistor, for example the start of the record is detected and the tonearm lowers properly, then the problem looks to be in the circuit that responds to the end of record signal. Just guessing but I think that points to the run-off stop circuitry on the main board. Page 5-2 of the service manual lists 1TR16 as a component to check for that type of failure. If you have the service manual and some test equipment I would monitor the components in and around 1TR16 when the stylus is at the end of a record. 

-sonavor

riis
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riis replied on Fri, Feb 5 2016 10:54 PM

Thanks very much for your help. I'm afraid I won't be able to solve the problem as I know nothing about the electical parts of the Beogram.

sonavor
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riis:

Thanks very much for your help. I'm afraid I won't be able to solve the problem as I know nothing about the electical parts of the Beogram.

I think you have the problem narrowed down to the specific area. Since you are in Denmark I would contact Martin (Dillen on this forum) and see what it would cost to repair it. The Beogram is well worth getting back to full working condition.

-sonavor

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