Beomaster 6000 (2702) Remote Control

[joupar]

Hello everybody!

I’m in the middle of a project trying to reproduce the remote control for my 4 channer Beomaster 6000 from the 1970’s (see the pic attached taken from the interweb). This is the one that uses modulated ultrasonic tones around 47 kHz to pass the commands

This remote seems to be a hard one to find nowadays. Or, if found the prices tempt to be very high. This is why I decided to try to reproduce it

I have either acquired, ordered manufactured (PCB) or produced by 3D printer by myself all other bits and parts besides the ultrasonic transmitter/microphone used in the circuit. It is of a old type which uses around 180 volt bias. It goes under the B&O part number 8970002

Now, is there anyone inside the community who has got experience with this device? Or the better if anyone happens to have reserve parts for Beomaster 6000 remote receiver or this transmitter . Receiver because it seem that B&O used the same part in transmitting and receiving ultrasonic commands

Or is there another known type of a part which could be used in this circuit? Perhaps from an old microphone or so…?

Jouni

 

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[hcraig244]

Hi

I have a couple of these wonderfully over engineered amplifiers…..just love them. I only have one commander however that was gifted to me by the good doctor, I’m taking the view you have neither commander or receiver board in you 6000?…..I could look inside mine and see if the microphone has any markings if you wish….

Craig

• This reply was modified 4 weeks, 1 day ago by hcraig244.

[joupar]

Thanks hcraig244,

I do also love these over-enginered Beomasters. It is challencing ant intresting to see how they constructed these design beauties. You need many hours of work, but when the device is your own, it does not matter at all…

My Beomaster has got the reciever card in it. Only the remote was missing when I got it. So, I’m interested in if they used the same ultrasonic element in both. Ultrasonic tranciever in one term in that case

I would appreciate a lot if this could be confirmed first. It would narrow my search. And a photo inside the reciever would be nice…

Jouni

[hcraig244]

No worries Jouni

Not the best images but take a look….

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[hcraig244]

Couple more

 

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[hcraig244]

Oh….and a 15v battery

If I can help anymore let me know

Craig

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[joupar]

Thx Craig for your time and effort

The pictures are absolutely fine and helpful. Now I can try to replicate the inner parts also like they were originally done

I now have to investigate these pictures throughly and adjust my design

That battery is indeed 15V. I have understood that this kind of batteries were (originally) used in photo flash devices, and are now as original kind of obsolete. But I think it could be replaced e.g. 3D-printing a ”case” which can hold ten 1.5V button batteries…

Jouni

 

 

[hcraig244]

Jouni

I bought the 15v battery relatively recently, amazon I think VARTA No 4074.15v.V74PX

Craig

[joupar]

Hi again Craig,

That Varta battery you mentioned I had not any idea of. But thanks for the info. I’ll look up it

The design base material, pictures, schemas and part listings I had acquired for this reproduction of mine, had a battery shaped a bit more squared than this Varta battery. It was noted as type ‘W10’, which is a photo battery. And that was what I was looking for

I can see from the pictures you took that the battery holder base in your Commander is round shaped from the bottom. So suitable for that Varta battery. Might there have been a few different versions of these Commanders…?

Any way, please, if it does not make big trouble, could you take for me some more photos from inside of the Commander? I’m most interested in looks straight from the side, so the ‘layers’ inside of it could be seen

And what would be the overall measurements of the Commander in millimeters?

I’ll soon be able to show some pictures of the design of mine. Ready for 3D printing and PCB ordering. If anyone is interested in…

Jouni

[joupar]

Hi again all,

FYI, I ‘d like to post a picture of my design to replicate this Beomaster 6000 Commander remote module.  Here you have it

Based on the information I have acquired this far from various sources, especially mentioned here Craigs efforts to send the pictures…

For the production of it there will be needed a water cutter to make the faceplate with slots from steel sheet metal of 0.3-0.4 mm thick, 3D-printer for aluminum filament to produce the upper case half, and ASA/PET-G capable 3D-printer for the inner parts and the bottom case half

Hardest job here would be to locate the ultrasonic transducter suitable. It should have the inner capacitance 60-90 pF, the circuit to be tunable right

The coil on the other hand can be easily handmade. I have calculated it from the information that I have

Estimated:

• oscillator’s base frequency is around 47 kHz, so the coil inductance should be around 20-24 mH based on the given capacitance values in circuit
• the coil measurements are: length of 17mm, empty core diameter of 6mm, tunable ferrite core inside it of 4mm diameter (e.g. from an old transistor radio)
• voltage on the inner most coil N1 is around 30 vac, and over the ultrasonic transducter 400 vac/200vdc, thus the coil turns ratio N1/N2 is around 1/13
• the outer most coil N3 of 6 turns (is seen from the pictures)
• the feedback ratio given to the circuit from N3 must be roughly estimated, but it is somewhat tunable with the trimmer potentiometer in circuit. Though, I would estimate it to be in this kind of a circuit less than 0,5%. So N1+N2 could be 150-200x N3
• the outer most coil I estimated to be of 0.4mm enameled copper thread and the other two inner coils of 0,10-0,15mm thread

Then the windings that would work here are approximately: N1 = 90 turns, N2 = 1000 turns and N3 = 6 turns…

The body of the coil can be 3D printed

The coil and test circuit of the base oscillator is under work at the moment…

Thoughts?

BR

Jouni

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[hcraig244]

That’s a very ambitious undertaking Jouni..

All credit to you, the cost of producing such a piece must be high…not including your time of course which you give freely, my few dealings with custom laser printed items has always resulted in high costs.

I will provide the images you have requested today……keep the pictures coming.

Craig

[hcraig244]

here we go…

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[hcraig244]

some more

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[hcraig244]

last

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[joupar]

Hi Craig and all others,

Yes I know the task I took is quite big. And not necessarily cheap. But what do you do if you are devoted and enthusiastic B&O collector and hobbyist… 😉

I do have a 3D printer of my own. It helps here

And what comes to the water cutter I mentioned, there are here in Finland some educational institutes for adults which do have that kind of devices. Actually one is quite near me. They call these ‘FabLab’s, Fabrication Laboratories that is, where they teach digital based fabrication and manufacturing, or something that way. And they have these “timeslots”, when there are not education going on on those premises. Then an “outsider” can reserve time to do one’s own fabrication tasks. For a minimal cost that is. Because those FabLabs are funded from public society funds. This also helps a lot in costs…

But this project actually started from the thought “How hard at all can it be…” to replicate this Commander. Thus, no time costs at all…

Thanks Craig for the pictures. They are helpful again

Jouni

 

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