[Madskp]

pilatomic wrote:

Slowly reverse engineering the Datalink protocol used between the BeoMaster / BeoCord / BeoGram 5500, for a secret project.

sounds very interesting. Looking forward to more info.

Are you avare of these two projects?:

https://github.com/jensjoachim/B_and_O_Projects

https://github.com/toresbe/datalink

[Madskp]

Madskp wrote:

So my guess is that to use the BM4500 as a slave unit it should be conencted to a Master unit via the AUX socket. However a normal Audio Aux cable can not be used as this will connect Audio in to Audio in and Audio out to Audio out. I have to make a crossed cable and do some more testing. update will follow

Finally got some time on my hands to make a Crossed Audio Aux cable to be able to test the BM4500 as a slave with another non Masterlink Beomaster.

The cable pinout looks like this:

The inputs and the output are switching places whereas the data and the ground pins all connects to the corrosponding pins on the other connector

I used a Beocenter 9300 as the Master unit (set to option 1) and the Beomaster 4500 as the slave unit (set to option 1.6).

A picture of the setup

And it works :-). I can control the radio channels on the BC9300 from the BM4500 when I use Link + commands.

Next up I wonder how it will work if MCL2 link rooms are connected to the speaker 2 connectors on the BM4500. I guess there must be some kind of limiting factor somewhere since B&O says that option 6 must no be used.

 

[Madskp]

Just to let you know a fellow Beoworlder offered to take over the project in exchange for some spare part to other projects, so I have choosen to focus my time on these instead of trying to revive this BM5500 myself.

But thank for the input

[Madskp]

Rolf2 wrote:

You may check the sw version of your BM. Talking about options 5 and 6, those were only available in earlier 1-way versions. 1-way function only had been included in the BM 4500 with a sw version below 2.1.

Thanks for responding. I was not aware that the BM4500 also had been in a one way version initially. Interesting.

Mine is labeled SW 1.6 on the back, and looking at old forum post I can see that when the 2 way communication was introduced in SW 2.1 the ability for the BM4500 to act as a ML slave was removed. Thus I’m pretty sure mine is a software 1.x even if it has had a software upgrade along the way.

This fits me fine as I have no 2 way remotes, and for my use case it could be great to have it act as a link room in the setup.

Jus to see that this function actually worked I connected it to a BS Ouverture via a Beolink 1611 converter. With the BM4500 in option 1.6 and the Ouverture in option 1 I cold start the sources on the BS Ouverture from the BM4500 with the use of link + Audio commands while both units would still use local sources with normal audio commands. Great 🙂

 

[Madskp]

Madskp wrote:

I wonder how the BM4500 should be able to work as a slave in a MCL2 system connection wise as it does not have the MCL input as the MCL2AV has? It sees wierd to be mentioned in the manual if the product is not hardware wise ready for it.

A quick test to see what happens when using option 1.6 or 2.6.

When the BM4500 is in option 1.5 or 2.6 it will not react to Link + audio commands.

But when I set it to option 1.6 or 2.6 all Link + Audio commands activate AUX on the BM4500.

Further more the schematics in the service manuals show the data pins on the AUX socket and the speakerlink (MCL2) sockets are connected so all signals are passed between these two sockets.

So my guess is that to use the BM4500 as a slave unit it should be conencted to a Master unit via the AUX socket. However a normal Audio Aux cable can not be used as this will connect Audio in to Audio in and Audio out to Audio out.

I have to make a crossed cable and do some more testing. update will follow

[Madskp]

Ok that makes sense. just being curious about the usecase for that connection

[Madskp]

Great to hear that it is now working ?

I am wondering though why you would need this connection when the speakers are connected to the Beoport. This connections is not shown in the manual for the Beoport and the audio out port was originally blocked with a label from the factory

[Madskp]

Hello

just for clarification, do you use the audio out minijack socket on the Beoport for this connection?

And also, do you not have speakers connected to the Beoport powerlink ports or headphone jack?

one simple test to try if you haven’t allready done that would be to connect another source to the line in socket on the PC just to check if something is different

[Madskp]

Hello and welcome to the forum

The 1656 Beolink Passive should work just fine for your purpose. One important note is that you need a fully wired powerlink cable between the ouverture and the 1656 for it to work.

you might also be able to find the box named as ML-MCL converter with a different type number. It is the same box, it can just be used for other types of setups also. If an Ir eye is bundled with a ML-MCL converter you wont need that in your setup.

hope this is helpfull

[Madskp]

Ok so I removed R34, and the relay was not clicking when I turned it on.

what I probably didn’t notice after the last incident was that there was no light in the display anymore.

I could meassure 5V supply to the display board.

And then I looked  away for 2 seconds and fireworks started in the back of the amplifier.

From what I can see two of the big grey resistors has burn marks

Unless anyone thinks this is fixable I think I will let this BM5500 rest in peace.

One side note. It is a prototype unit with Red labels that my father got when he worked at B&O. I have noticed that there are things that doesn’t line up with what the diagrams show. For example there is a transistor callled TR5 on the display board with connections to two LED’s. This is not shown in the digram

[Madskp]

Hello and thanks for the input.

I haven’t touched it since I made the post, but will try to investegate further based on your advice and post my findings

[Madskp]

speedsixdave wrote:

Hi all, A quick update on this. I finally have a working MCL connection between the BC9500 and BL3500, after some shenanigans and possibly killing some of the display on the BC9500 (see seperate post). It really was as simple as making a single cable from the 3-pin din MCL speaker plugs to the 8-pin din MCL plug, but as it was the first soldering I’ve done in about 30 years it did not go smoothly. Eventually I realised I had a short between the pink (DC) and yellow (left signal +ve) pins (via the metal DIN casing) and now the thing seems to work ok. As Mads pointed out the pink wire does nothing in the BL3500 so the fact that I broke the pink connection in the 8-pin DIN plug while trying to fix a loose green (right signal +ve) connection does not matter. All very much above my skill and dexterity levels, and I have new burns to prove it!

Great to hear you  got it working. The 8 pin DIN plug is a pain in a.. with the thick MCL cable so fully understandable that it can cause problems. Sad to hear that it backfired on you BC9500

[Madskp]

you will need a fully wired powerlink cable to activate the MCL2P. That will most likely be the problem

[Madskp]

matador wrote:

On question thought: did you manage to get the BL3500, working as it should with the WL1? That mean having it wirelessly connected to a master link master and having the WL1 starting the 3500?

I you refer to what is shown in the Bl3500 user manual I haven’t tried that setup as I gues it will work and is a little outside the scope of this thread.

But to clarify the setup I tried I have modified the sketch from the user manual:

The Powerlink cable has to be fully wire for it to function as it needs both the normal powerlink on signal on pin 4, and the data signal that is on pin 6.

This setup works, but I can’t replicate it with powerlink outputs from BL active, MCL2AV or BS Ouverture, so the data signal from the W1 must be the key for this to work.

[Madskp]

After testing with the BL W1 I am now at the point where I have no further open ideas to test for the topic of this thread. Therefor any suggestions for further testing is very welcome..

Of course if I get any Ideas myself I will continue with them

[Madskp]

Madskp wrote:

So it might be a combination of the 5V on pin 4 and the datasignal on pin 6 that has to be present to turn the BL3500 on via powerlink, and that data signal must be different from whats comming from a BL Active, MCL2AV or any powerlink equipped BS, BM, BC

And just to be sure that both the Powerlink On signal on Pin 4 and the data signal on pin 6 in the powerlink connector is needed at the same time to activate the BL3500 MKII from the BL W1 I tried to make an adapter cable with  only pin 4 and the 2 ground pins (2 and 7), and after that a cable with only pin 6 and the 2 ground pins.

I was not able to activate the BL 3500 with any of these cable configurations which supports my earlier statement that signals on both pin 4 and 6 are needed to activate the BL3500 MKII

[Madskp]

Some aditionel testing with Bl3500 MKII and BL W1.

The same setup as before with the BL3500 and BL W1 connected via powerlink. In addition I also connected the BL3500 to Masterlink and set ML to on via the submenu Menu, 0, 9, GO to see the Behaviour.

In this case I cannot activate the BL3500 via the BL W1 powerlink conenction

[Madskp]

Try pressing Menu, 0, 9, GO to see if Masterlink is on or off.

If it is off you can change the setting with up or down arrows and accept with GO

You can also try to see if there is a Masterlink error by pressing Menu, 0, 2, GO.

This will either show NO ML, ML ON or ML error 1-4

[Madskp]

Madskp wrote:

One odd thing I noticed when measuring voltages was that pin 1 on the BL W1 Powerlink connector was 12V which seems high, but the BL3500 MKII doesn’t seem to have anything connected to pin 1 so might not mean anything in relation to the BL3500

Just to be sure that PIN 1 in the powerlink connector is not used for turning the BL3500 MKII on I decided to disassemble the BL3500 so I could get full access to the plug PCB. I found out that most of the parts have to removed from the aluminum enclosure in one piece

From there I could unscrew the plug PCB.

There is no sign of connections from pin 1 of the DIN connector on the PCB. To verify further I also tried to do continuity test from pin 1 to all other connections, test points and vias on the PCB, and found no place with connction. So I’m about 99.9% sure that Pin 1 has nothing to do with activating the BL3500 MKII via Powerlink.

 

[Madskp]

Did some more testing today measuring voltages as I turned on and off the system.

The BL3500 is recieving the 5V on its powerlink PIN 4 when a source is selected from the W1. Also the data signal on pin 6 seems to change in voltage when turning on and off.

I can also see a change in data signal voltage when changing volume.

For good measure I tried to apply 5V to pin 4 and 7 on the powerlink connector without anything else connected to the BL3500, but nothing happened.

So it might be a combination of the 5V on pin 4 and the datasignal on pin 6 that has to be present to turn the BL3500 on via powerlink, and that data signal must be different from whats comming from a BL Active, MCL2AV or any powerlink equipped BS, BM, BC

One odd thing I noticed when measuring voltages was that pin 1 on the BL W1 Powerlink connector was 12V which seems high, but the BL3500 MKII doesn’t seem to have anything connected to pin 1 so might not mean anything in relation to the BL3500

[Author]

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