When vintage B&O goes wrong (part 1)

As I am known to do, I take the simple and overly complicate it. As such, I have a Beosystem 3 connected with my Beosystem 6500 in my living room using a 1612 converter. I also have 3 MCL2 remote rooms connected so I can listen in my dining room, kitchen, and main bathroom. When it works (most of the time) it is fantastic - music from any of my sources in many rooms.

This past week it went all wrong and could use some sage advice. After listening to music in the kitchen, I pressed the wall mounted IR receiver and although it muted the music, when I held it down for a few seconds, it did not put the Beomaster into standby as usual. I went to the living room and tried my Beo4 remote, and no control. None of the audio only selections seemed to work. Any video selections on the Beosystem 3 worked just fine in the living room, but did not route through the BS6500 to the remote rooms.

There were no lightning strikes or power surges, but just in case, I power cycled the system, brought the BS3 up first, then a few minutes later the BS6500, then a few minutes after that the 1612 converter. No better. I verified the video and audio option settings - they were correct - still no better. I reached behind the BS6500 and momentarily unplugged the left MCL2 connector and viola!, the system seemed to work properly for a few minutes at least. I always seemed to have control of the BS6500 locally, but it wouldn't route through the BS3.

Fearing the BS6500 was in need of TLC, I replaced it with my spare BS7000 (I know, a spare? yeah) and at first everything seemed to work, but then later that day the same thing. Some times I could not control audio from the remote rooms manually, or by remote. The CD6500 would not start from the remote either, well it would start and quickly stop (the dreaded cap issue? Sure, why not?). I made sure all the settings were correct and found nothing. This time I unplugged the MCL2 left connection and no improvement. I unplugged the right MCL2 connector and when reconnected - everything worked again! 

So, the MCL2 loop when having an issue can not only affect the routing to the remote rooms, but could also prevent the BS6500 from responding to remote control commands and from routing through the BS3. I do not think my original BS6500 was really at fault - I'm guessing it's one of the MCL2 remote boxes going intermittent. I just love intermittent issues! So my plan is to swap the boxes one at a time until I get long term normal behavior. Sound reasonable? Any other advice?

So after disconnecting and reconnecting the right MCL2 speaker wire, I’ve had a few days of normal operation. I didn’t really fix anything, but I can’t dispute the results. Does anyone have any theories on why this action would restore stability to my system? That would help me sleep at night .

Two days of normal behavior and then the remote receivers stop working again. I disconnected both MCL2 wires this time, but it still balked. I turned the BM on manually, and then got some level of control - I could mute, but not adjust the volume. At least I should know pretty quickly when I have the issue resolved.

2 independent systems 2 simular problems: did you monitor the voltage of your mains over a period of time f.e.? or could other external factors play a role?

As sometimes happens, it looks like there were two problems. I first disconnected the second two relays from the MCL2 circuit and everything seemed to work properly for a few days. Then I replaced the last relay box on the run and everything seemed fine now - all remote rooms worked and responded to remote commands. Then I noticed I only had audio from the left channel. I checked my connections and confirmed everything was fine. The  I noticed when I moved the speaker plugs on the back of the BM7000 I find it acting like a loose wire or connection. I opened up the right plug and all the solder connections to the pins look fine, so I guess the issue is in the BM DIN connector. That will probably go away when I replace the BM7000 with my original white BM6500. Now I'll run everything for a week or two before declaring victory, but I'm encouraged. 

Intermittent problems are a pain - I had something similar with a Beolink Active that was working when I uninstalled it - then changed my mind and reinstalled it - turned out a wire in the IR eye had come off - fixed that only to find that one in the plug had also come off! all working now.

One problem I had that caused intermittent behavour with my BM6500 was when the battery fails - I kept losing the programming - unusual for both of yours to have the problem, but maybe worth bearing in mind if you get funny problem in future

Now on occasion I lose the right channel in my remote rooms. If I just touch the MCL2 wires it will come back. Not sure where the continuity break is, but I’m sure it’s fixable.