I like Bang and Olufsen equipment, despite the fact that it’s not always easy to work on, on the plus side though, service manuals and circuit diagrams are easy to find and download. So this Beocentre arrived on my doorstep with a fault of “a loud buzz in the speakers and nothing else”. Well that sounded like a power supply problem and that’s where I started looking, it was surprisingly easy to get apart so that was a good start. Casting a quick glance over the power supply all the capacitors seemed to be in good order, of course this means nothing, I come from a time before ‘domed’ capacitors so it was out with the oscilloscope to monitor the voltage rails out of the power supply. I soon found the offending capacitor and on removal it was obvious that it was faulty because it left one of it’s legs behind in the panel!
So now for a quick test on FM radio only to find it was only working on one channel, so out came the oscilloscope again, starting at the outputs and working my way back…all the way back to the FM stereo decoder where a coil was found to be open circuit. Replacement of that had a good working radio section and a quick test of the tape decks showed they were both working well. All that was left was to repair the speaker leads that the owner had brought in with it, these had been extended by twisting the wires together and taping them up – an accident waiting to happen. I chopped out the joints and rejoined using proper solder joints and heat shrink tubing. That was it, another lovely old Hi-Fi up and running and back with it’s owner.
