[filip_kbh]

I replaced the 3V battery – didn’t actually need to as it measured 3.1V after all these years still.

Yes, I checked the option.

The display is okay.

I replaced on the front panel these capacitors – they all had very high ESR measurements

C15 1uf/100V ESR 40.3 BAD
C19 2.2uf/63V ESR 14.2 BAD
C20 10uf/63V ESR 2.30 BAD

After this, I checked that the amp was working but I did not check 2-way communication.

I also replaced 2 capacitors on the CPU board – both of them gave no ESR whatsoever:

C1 100 uf/10V – measured capacitance 14.7 – way out of spec

C57 47uf/10V – measured capacitance 11.7 – way out of spec

So, I presume that I may have done something wrong with one of these capacitors – or they need to be a certain brand. The two from the CPU board were the blue Philips type as well as two from the front panel.

 

 

[filip_kbh]

Hey – I also show as Bronze member but am in reality Gold member. I am sure the programming will work out at some point.

[filip_kbh]

Set the Beomaster to Option 1. On your Beo4, press Standby button (the red dot) and List at the same time. Your Beomaster will turn off, and the Beo4 will show Option. Press 1 and Store or Go (I don’t remember).

[filip_kbh]

Oh crap – I don’t want to spend that much time on it since I rarely record anything on tape. Thank you for the answer.

[filip_kbh]

Not sure what you mean by “drive pins” … a picture?

[filip_kbh]

3. Yep. Those red caps will need replacement.

The Idle current trim pots are marked 3R124 and 3R224 on the board. Replace them with trimmers of similar ohms value. Read in the service manual how to adjust the required 10mV.  You can download the service manual if you are a gold member (and at the same time help keep this site up and alive)

[filip_kbh]

1. Do you know anything about electronics? Otherwise, it is probably best to leave it to somebody professional who can fix it for you before you make matters worse.
2. If the Beocenter shuts off after a few seconds, it is usually a sign that somehing is pretty wrong, and it shuts down to protect itself. This can be because of many things but one of the main suspects in this particular stereo would be the idle current trimmers corroding. When that happens the idle current becomes too high. These two trimmers should be replaced, and the idle current adjusted afterwards.
3. Have you done a visual inspection of suspect components? The reason that I ask, is that a few of the red Roederstein capacitors look very suspicious to me – they look fried. At this point in time, it is fair to say that all electrolytic capacitors in the Beocenter should probably be replaced.
4. If you have not discarded the original relay, I suggest that you clean it with very fine (wet) sandpaper where the metal parts meet each other. It’s an easy fix, and your relay will become as new.

 

.

 

[filip_kbh]

Strange – it seems that the problem fixed itself. Now it works every time.

[filip_kbh]

I also finally got around to adjust the no load current to the specified 11 mV. The trimmers were quite dirty it seemed so I gave them a big splash of contact cleaner, waited some minutes, and then it was possible to adjust the no load current without it jumping like crazy.

However, after I put everything together, I have a rather irritating and interesting problem: After some time, the two buttons on the front panel do not work which means that I cannot turn the BM7000 on with the left button. If I then turn it on with a remote control and turn it off again, the left button will work for some time, after which it gets unresponsive again. Any ideas why?

[filip_kbh]

I think it sounds more like a dirty lens. I do not know the Beocenter 9000 but if it contains a CDM 12.4 mechanism, I linked to a video on how to clean the lens from the underside, including the mirror in the thread called How To Fix The Laser In Beosound 9000.

[filip_kbh]

Finally got around to removing all of those capacitors.

Apparently C67 and C68 were never fitted from Bang&Olufsen, so I guess they must have suspected that they were not necessary.

I am listening to my BM7000 now, and I agree that it takes away a layer of ‘muffleness’ – it’s like removing a blanket in front of the speakers.

Thank you for suggesting this mod. I wonder why B&O fitted the board with those capacitors in the first place.

[filip_kbh]

It’s C2103. Indeed it’s the blue one to the left of the microprocessor on the above board. A very simple capacitor to change, as long as you get the right one 🙂

[filip_kbh]

I spoke too soon. It worked on my living room table.

And I have narrowed down the problem. I have an Almando surround box II connected to Powerlink. When that is plugged in, the datalink does not work. Argh.

[filip_kbh]

Just reporting back. Everything works now. Still there is the high-pitched noise that I presume may come from the display of the BL3500. The display does not show the clock – but I guess it would take it from a video source and not just the BM7000?

I inspected the pre-amp board of the BM7000 and could see multiple cracked solder joints, also for D5, so I presume that is where the fault was.

[filip_kbh]

Thanks a million. I really appreciate the help.

/Filip

[filip_kbh]

Great – I will order those parts and let you know how it goes.

There are several versions of the BC547 – an A, B, and C version. Which one to choose? Or will they all do?

[filip_kbh]

I checked for continity on all pins.

Reconnecting the cable, there is now stereo sound in the beginning until the 3500 randomly shuts off. I obviously don’t know if I connected the different ends differently this time around. Again, it refuses to turn on for more than 1 second.

[filip_kbh]

Yes, I also tried that. Pressing the mute button on the panel, I can listen to the CD that I am listening to on the BM7000 but there is only sound from the right channel. But I can’t turn it off by pressing mute again – there is no reaction. Now it turned off by itself, and I can’t turn it on again by pressing mute. Very strange.

[filip_kbh]

I have now re-done the option settings while everything was connected to mains. Pressing Radio turned on both the BM7000 and the BL3500 but the BL3500 shut off after a second.

Regarding the previous question, the datalink cable is connected to the socket called AUDIO OUT LINK on the 1611 box.

[filip_kbh]

I just tried. Disconnected everything. Turned on the BM7000 and set it in A.OPT1. Disconnected it from mains. Connected the BL3500 to mains and set it in L.OPT6. Disconnected it from mains. Then turned on BM7000, thereafter BL3500 and finally the 1611 box. It still does not work – argh, this is so frustrating.

[Author]

Posts