I'm in the middle of restoring a Beomaster 6000 4-channel unit. I have a few Beograms (4002, 4004 and 6002) that I have restored already.
I knew this unit would not be the easiest one, but everything is working now (well...almost.. waiting for the new belts to arrive). One issue that I can't seem to solve is the following: when depressing the hard, black switch on the top panel for LO filter, a very loud cracking sound is heard through ALL the speakers. Does not matter what volume I'm setting. When releasing the switch, no cracking at all. The filter seems to work and cuts of the (very)low frequencies. What could cause this sound? Can't imagine something mechanical broken inside the switch since I can hear it on all channels. Anybody that can help me out?