BM5500 – Help Needed – Scotland

[billfraser]

I’ve enjoyed a much-loved Beosystem 5500 for 35 years.  A recent close lightning strike has left the BM5500 rather sick.  I’d dearly like to get it working again, but I’m a mechanical engineer – not an electronic one – and would need some help.  So I’m trying to find someone with the necessary knowledge and skill to diagnose and repair the problem.  I live near Inverness in Scotland, and would gladly deliver the unit to anyone within several hundred miles if they could assist me diagnose and fix the problem.

Symptoms have been as follows:

1. A very close lightning strike caused an audible “pop” from within the system, which was connected to the mains but in stand-by mode at the time.  There was no smoke or smell or any other indication of burning.  A quick check after the storm had passed suggested that all was still functioning OK.
2. However, a few days later the tray of the CD5500 wouldn’t open, the red LED on the BM5500 wasn’t lit, and the BM5500 wasn’t responding to any commands from the MCP.
3. Neither of the two fuses in the BM5500 was blown (I’d suspected that the 250v 2amp fuse on the power supply might have suffered when the lightning struck, but it hadn’t).
4. After I’d put the cover back on the BM5500 and connected the other system components back up to it, I connected everything back to the power supply, and was pleasantly surprised to see all red LED’s light up on the four front panels – including the one on the BM5500.
5. However, when I then selected Radio on the Master Control Panel, nothing happened, and the LED on the BM5500 went out.  Trying to select any of the other sources (BC5500, BG5500, or CD5500) using the MCP only produced a “NO CONTACT” message on the MCP, despite the fact that the BC, BG, and CD all appeared to be independently operating normally.
6. After having left the whole system disconnected from power for a few hours, I reconnected power back on to everything.  The indicator LED’s on the front panels of all four components lit up as normal.
7. I then again tried selecting Radio on the MCP, and to my surprise the radio immediately played and was operable from the MCP completely normally.
8. But when I then tried to select the CD5500, a relay started clicking in the BM, there was a sudden cacophony of very loud static noises from the Beolab Pentas, the little red LED’s on all four system components went out, and the whole system went dead.  So the BM is obviously much sicker than I’d feared.

Can you suggest what may have happened to cause the problem?  Could you help me diagnose the defective components?  Would you be able to repair it for me?  Thanks in advance for any help you can offer!

[Die_Bogener]

billfraser wrote:

1. But when I then tried to select the CD5500, a relay started clicking in the BM, there was a sudden cacophony of very loud static noises from the Beolab Pentas, the little red LED’s on all four system components went out, and the whole system went dead. So the BM is obviously much sicker than I’d feared.

 

 

You have a bad power cord/box/wallbox…

When all 4 red lights fail, it’s a general power fail of the 220V cord.

[billfraser]

Hi Die Bogener,

Huge thanks for your help.  I’d previously checked all connection terminals inside plugs and sockets associated with the incoming power supply to the system, and all were good.  I guess because the problem started following that close lightning strike I’d convinced myself that some damage had been caused inside the BM5500.  Whe the fuses inside the BM were good, that’s when my pessimism about the complexity of the problem set in, and I failed to spot that – if the LED’s had gone out – it had to be because there was no incoming power.  After your helpful steer to the source of the problem, I went back and eventually discovered that an intermittent fault existed in the incoming mains lead from the wall socket – a mains cable that had been completely undisturbed for the past twelve years.  I changed out that cable, and the whole system is now working perfectly again, just as before.  I was so happy that I spent the whole of the rest of the evening listening to my favourite music!!  Why that incoming mains cable developed such a fault remains a complete mystery … I’m going to pull it apart to satisfy my curiosity.

Again, my most grateful thanks for your help.  Thank you.

[Author]

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