ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
So here's another thread among many where someone (I) am asking a question about the Master Control Panel 5500.
My problem is: The radio button is stuck. The remote constantly broadcasts to turn on the radio function and nothing else.
I bought the MCP used, and after opening it up, it's obvious that someone has been messing with it. There was a piece of black tape over the spot on the board where the radio button is suppose to contact, and the "bubble button" is missing completely.
Any help or advice would be appreciated.
Full photo album found here: http://s934.photobucket.com/user/beitie/slideshow/Audio%20Equipment/Bang%20%20Olufsen%20MCP
https://youtu.be/KnNXIOYf6mU
I say, scrap an old TV remote and get the missing part from it!
Jacques
That would be a good start, yes. I like that idea.
However, I think the problem is deeper than that. Even with the button removed from the MCP, and black tape covering the push pad, it still constantly spams the radio function.
I'm not really great at putting YouTube vids into my posts, but I'll try it again.
https://www.youtube.com/watch?v=KnNXIOYf6mU
The center pad is normally covered by the small springy bronze plate.What happens if the black tape isn't touching the center pad of the Radio button?And what's that orange powder-looking stuff? Something spilled? Acidic?Martin
So far I've tried the MCP with the black tape over the pad, and with out the tape entirely. I've also cleaned the contact pad with electrical cleaner. Still does the same thing and broadcasts the radio function constantly.
I did not notice orange powered? There are no physical sings of battery leakage. It's pretty clean.
So the contact was probably removed in an attempt to make it stop sending.The problem must be elsewhere, then.Try putting an ohmmeter across the contact points, compare with readings from other buttons pads.It looked like orange powder on the backside of the front panel in your photo. Perhaps it's just light reflections.Martin
When I used my ohm meter, the circuit did not have any connectivity that I could find. (Display stayed OL). After looking at the picture again, I can see how there is some light that makes things look somewhat orange. Probably due to my camera, it's pretty old for a digital, and the picture quality isn't up to par.
The person who sold it to me texted me back last night saying that he'd refund me that part of the purchase. I've found another on flebay, so I'm just going to give up on this one and try the next.
Since I have the proper Beocord 5500 and a Beogram 5005 now, I have been able to listen to the system, and it does sound good. Though there may be a few small issues with the Beomaster 5500, but I'll post about them when the time comes, and with a proper thread title.
Thanks, Andrew
Update Saturday morning:
The new MCP 5500 came in this morning. I was very happy when I put the batteries in, and it didn't immediately change the input to radio :) All the buttons seemed to work just fine, but I was unable to adjust volume. So I took it down to my workbench, opened it up, and took out the microswitch from the control wheel, and cleaned it with contact cleaner and a toothbrush to get the bristles between the contact points and clean whatever carbon might be on it.
I put it all back together, and started over once again. Still no volume control.
Well, when I was playing around with the other MCP, I was able to adjust the volume from time to time. Not very well, but I could get it to work. So I opened up both, and swapped the microswitch from the bad MCP to the good MCP. Still the same issue. No volume control.
Ugh this is frustrating. I just want to listen to the system, it's been a solid 2 weeks now.
I'm starting to wonder whether the BM should be at fault, or it's very hard luck indeed.
The Beomaster may be at fault for the volume control issues. Admittedly, this is my first Beosystem, and there are things about it that I'll need to learn... So I created a short video to show it off a little and show the issue I'm having. One of the things I've noticed, whenever I get the Master Control Panel's screen on and try to adjust the volume, the screen blinks at me until I stop adjusting the volume. So it very well may be Beomaster related.
I'll put the URL to the YouTube video here... I've been able to edit in YouTube videos, but for some odd reason they never show up in the post, if anyone has a way to help me with that, I'd appreciate it.
https://www.youtube.com/watch?v=TwAhpEQxQWI
Is anyone nice there over the Pond willing to lend Andrew a Beolink 1000, just to be sure?
It sounds as though the second MCP (and possibly the first one) needs a new infra red opto coupler on the volume control. When you operate the volume control the microswitch which you have cleaned tells the MCP that you are turning the control and the direction in which you are turning it, the actual control pulses are generated by an alternating black and white printed strip around the outside of the wheel passing in front of the opto coupler. I think what happens is that dust collects around the wheel and causes a static charge which eventually kills the opto coupler! The part number for the opto coupler is Siemens SFH900-2 (SFH900-1 also works fine) and they're very hard to find! The good news is that they're not hard to replace and if you can't find one I've got one. :-) If you PM me with your address I can send you one.
Ben
I see what you are saying Beoselecta. Maybe before I have one sent to me I should try to swap the one off the bad MCP to the good one. The good one did have some dust and debris in it that I cleaned out with a dust can. Also, while it wasn't perfect, the first one could at times get the volume indicator to adjust.
The Opto Coupler, is it the three solder joints that you are pointing at in the picture? Or is it the chip right next to it?
----edit----
After a google search of the Siemens PN, I see the item you are referring to.
Hi Andrew, sorry about the slightly vague photo, I couldn't figure out how to post two pictures! Here's a picture of the other side of the board (yes, it's the three solder points I'm pointing at). While it's certainly worth trying the one from the other MCP I've got a feeling you might find that it's shot as well. From your description of how you could sometimes get it to work, it sounds like it's failing too! They do go bad quite regularly, I've just finished refurbishing four MCP's and three of them needed new opto couplers!
Here's another picture from the front this time.
Ah, I see. Is it like a hall effect sensor then?
Andrew: Ah, I see. Is it like a hall effect sensor then?
It is one! Also used in the Beomaster 8000 for volume and tuning, and on the Beogram 8000 to count motor turns. All very nice!
It's not in fact a hall sensor, it is an infra red LED and detector side by side in the same package and it "sees" the reflected light from the white areas around the wheel. A hall sensor is a magnetic field detector and works on a different principle altogether, although they can both be used to achieve similar results.:-)
Yes, of course, like the ones in old cassette decks that were used for auto-stop - Beocord 5000 anyone?
Beocord 5000? It's been a long time since the last one on the bench, but isn't that a round rotating magnet anda reed relay next to the tape counter?
Martin
Nope!
You're quite right, four pole magnet and reed relay on the early ones and eight pole magnet with hall sensor on later models!
Interesting. Though it sounds like I'll be taking the Beomaster 5500 and the MCP 5500 up to another forum member, and we will do some testing with his known good working equipment. I'll keep this updated when I know more.
Beoselecta, I think you're right on the opto coupler being the issue. I took the Beomaster to a friends place today, and we tried a few of his remotes on it, all worked just fine.
it’s on it’s way! I hope it solves your problem, I’m pretty sure it will. It’s also not a bad idea to replace the three electrolytic caps that you can see on the main PCB (something to do while you’re waiting for the opto coupler. ;-)
It's been a while since I've posted, but that's because I don't have a great update as of yet. I did receive the Opto Coupler from Beoselecta, and I spend a night working with my Dad who was an electrical engineer for many years taking out the old one and putting in the new one. When I got back home and tried it out, the MCP worked the same. Still no volume control.
I did purchase a good working Beolink 1000, and I use that with the MCP for now. It's not the most ideal situation, but it's working for now. I expect to have some free time this coming Thursday, and my plan is to check the Coupler that I removed, to see if I can bench test it in some way, just to learn how it works. Also, if something goes wrong with it, it won't be a total loss since it's the one that I took out. From there I'll look at the one I put in and make sure it's properly aligned in the case, and see if all the solder joints are complete. (Sometimes my Dad's eye sight isn't as good as it used to be, and maybe there's just a slightly bad connection on one of the leads.)
I'm defiantly not giving up on this yet, just struggling to find time with the Holidays around.
Make sure that your new opto component is not a fake.Yes, there are counterfeits around...
It's not a fake! I bought 5 from the same source in Germany and I've used three and they all worked!
http://www.ebay.co.uk/itm/SFH900-1-Siemens-Miniatur-Reflexlichtschranke-A15-2740-/221908813175?hash=item33aacbc577:g:Em4AAOSwT5tWF6Xt
Does it output pulses when you rotate the wheel?
I trust that Beoselecta got a good part and everything....
I have not tested pulses yet, mostly because I haven't re opened it up and looked at it since I put the Opto Coupler back on. I know I should, just been really busy with other stuff.
Also, I kinda messed up with the Beomaster, when trying to clean the mute relay. It came off the board, and I burnt some of the solder points pretty badly. So now I've got even more of a project :( Sorry this is taking so long, I'll try to get more figured out soon.
Thanks to Peter, I now have a fully working Beomaster 5500 again, and a fully working Master Control Panel 5500 also.
I took my equipment up to him today and he was able to fix my mute relay issue. Also, we pulled out the MCP and gave it a good look over, and he found a spot where some battery acid had wrecked a trace on the board. With a little extra soldering and some jumpers, it's now fully working like it should be :)
Thanks to everyone on these forums, it's been a huge help!
How did you get the tracer board off? I'm afraid of damaging mine.
Hi Beoselecta would you sell one Siemens SFH900-2 to me plz?
Thx
Dan
Correct part here:
LINK