[KolfMAKER]

Hi Jg1976.

You mention you can’t activate your BeoLab 3500 MK1 to listen to the MCL socket.

What does your display show after pressing ‘Menu > Menu > 0 > 4 > Go’ ? (This sequence should switch the BeoLab 3500 to the MCL input)

You could also check your BeoLab 3500 in ‘Test mode’. To do this press ‘Menu > 0 > 2 > Go’
And then check what you see in the display:

• ML OK = Master Link Connection is OK
• NO ML = Master Link is not connected
• Error 1 = Address configuration not possible
• Error 2 = Master Link data pulled low
• Error 3 = Master Link data pulled high
• Error 4 = Data collision on Master Link

If you see ‘ML OK’, the BeoLab functions properly, and your cable will probably be wrong. Connections and pins used might be the problem.
If you are handy yourself, you can make such cable yourself. Lots of info on this forum.
You can also ask @Steve of SoundsHeavenly to help you with the right cable.

 

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[KolfMAKER]

Thnx Guy.

Your right, I’d like to build something (small!) that handles auto-sensing and switching from stand-by to ON, automatically.

Location: The Netherlands
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[KolfMAKER]

@tuttivini

Thanks for your suggestions!

I know both sources sell trigger cables. I prefer to build something myself, as I want to integrate my whole setup inside the BeoLab 2. The smaller I can get things, the better. So I prefer to have a scheme for such and build something myself.

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[KolfMAKER]

I think you guys are right, about the two versions.

I also think the 2nd version is ‘easier’ to rebuild as the values of the capacitors are closer to components available.

Location: The Netherlands
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[KolfMAKER]

@Matador

Very interesting approach!

This is obviously the way B&O equipment handles it.
I would be very much interested in a electronics scheme, and make such to try it out.

Any chance you know how such would look like?

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[KolfMAKER]

Thnx very much Guy & Carolpa!

The Playmaker, BeoSound Core or Essence are unfortunately no options for this project. I am looking at a way to integrate the streaming completely inside the speaker casing. So no PowerLink cables, only a power cable and no boxes outside the speaker casing.

So I wonder if the 5v triger is something I can create somehow inside the BeoLab 2.

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[KolfMAKER]

Thanks for responding Die Bogener!

Questions:

1. So you mean to say, the only way to get  a permanent DC voltage is from the stand-by transformer? Or are there any other points which I could combine with a converter to bring it to DC 5v?
2. I think I have a BeoLab 8000 here with a defect standby transformer. Is there any way I can get a replacement stand-by transformer?

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[KolfMAKER]

Correction, Keith of course!

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[KolfMAKER]

That’s a great improvement Steve!

Thanks.

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[KolfMAKER]

Thnx @Mexking & @ RaMaBo !

Interesting that there are some differences in the values of certain components; between the info I posted in the start of this Thread and the info in the schematics & parts list of Mexking.

E.g.

• Capacitor #22 and 23 = 200uF/25v vs. 80uF/25v
• Capacitor #49 and 51 = 80uF/25v vs 1.6uF/25v

Is this correct?

 

Location: The Netherlands
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[KolfMAKER]

@Pilatomic

I am also looking for a permanent DC voltage on the BeoLab 8000. Can you help me confirm that?

Is it 15v DC after capacitor C66?

 

 

Location: The Netherlands
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[KolfMAKER]

Component search

I have done a quick check for components. There’s two challenges that I see:

1. Some components have values that are not very common any more, e.g.: capacitor 10uF/6.4v, 80uF/25v, 100uF/6.4v, etc.
2. I have to make sure that the sizes of the components chosen are the same, to make it fit on the original board remake.

Questions

(a) Can anyone recommend an online source where components with these ‘vintage’ values can be found?
(b) Are the diode types AO70 & AO81 interchangeable? Or does it depend on the version of the board which one to choose?

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[KolfMAKER]

Thnx for hooking in Mexking.

Where do you see ‘OA81’?

In the picture of the board, I can see something is printed in red on the component. But I can’t read it.

The B&O schematics says ‘OA70’. So I assume that is correct.

 

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[KolfMAKER]

I only have a picture, so I can’t look around the component.

But I believe you are totally right Martin. Your explanation makes perfectly sense!

Thanks again. I am getting closer to have all information for replicating the original!

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[KolfMAKER]

#22 & #34:

#31:

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[KolfMAKER]

Thnx a lot Martin, clear!

At the bottom right on the PCB, there’s two light brown capacitors: #27 & #34. And on the other side there also two: #31 & #32.

The schematics says:

• #27 = 22n
• #31 = 22n
• #32 = 0,1u
• #34 = 0,1u

The picture of the components says:

• #27 = 22uF, 160v
• #31 = 22uF, ?v
• #32 = ??, ?v
• #34 = 0,1uF, 160v

 

Questions:

1. I guess the picture is right and the schematics to be ignored on this point?
2. Are these ‘Orange Drop’ Capacitors?
3. Are they all 160v, and this it matter of the voltage of the replacement differs?
4. I guess #32 is also 0,1uF?

 

Location: The Netherlands
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[KolfMAKER]

Now making the full components list, I run into some questions. Obviously, a RIAA pre-amp of the B&O BeoGram 1000 and the SP cartridges are built to be matching with each other. So I want to make sure that I am selecting the right components. And if needed, to select an alternative that works.

So please help me out with this ….

(1) Component 3 & 4 (green box marking in the picture) have type name OA70, and looking at the symbol they seem to be shockley diodes.

Q: Is this indeed a shockley diode? Should I order exactly the same, or is a modern replacement recommended?

 

(2) Component 54 & 55 (white box marking in the picture) seem to be non-polarised capacitors with value 2,2nF.

Q: What exact type of capacitor is this? Should I order exactly the same, or is a modern replacement recommended?

 

(3) Component 7 & 9 (purple box marking in the picture) also seem to be non-polarised capacitors but with value 100p.

Q: What exact type of capacitor is this? Should I order exactly the same, or is a modern replacement recommended?

 

I would be grateful if you add an URL to components you suggest. Thnx!

 

Att: The PCB picture above, is a horizontal mirror of the schematics below!

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[KolfMAKER]

@Mexking

Thanks for sending the bottom view picture!
Yes, I am aware that my trace image has to be mirrored.

Question
The board side that sticks into the slot (so where the 8 tracks in a row are), has 8 notches.
Can you please let me know how deep they are?

I think they are a little less deep than the 6mm notch on the other side of the board.

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[KolfMAKER]

At the moment I am in preparation of making the PCB. My first step is to get the copper traces on a board.

Therefor I have to position and size the image of the copper traces perfectly. I have that picture (see picture below), but it has no outer/PCB border lines, so I have to find out how to size and position this image. (Obviously to get size and proportion equal to the original PCB)

Questions

1. Does anyone have such picture of the copper traces pattern, including outside/PCB border lines?
2. @Mexking: do you have a picture of the bottom side of the pre-amp board?

 

Location: The Netherlands
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[KolfMAKER]

Update:

I have now collected most information to reproduce the original B&O BeoGram 1000 RIAA pre amp extension board.

1. PCB layout (including drawing of the copper traces)
2. Components & specifications
3. All dimensions in mm of the PCB board

1 & 2 in this post.
3 in this thread:

BeoGram 1000 Pre-Amp PCB: what are the dimensions?

About components, I will continue in the next post in this thread.

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