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Problem with my Bose 901 equalizer serieIV

kinglizard's picture

I recently found a Bose 901 Series IV with the equalizer the speaker was fine but the equalizer is the problem,it got a loud huum noise,The noise is bigger when I push the Tape switch to monitor. I check all the ground connections and re-solder it nothing happen.What can I do.Thanks



Re: Problem with my Bose 901 equalizer series IV

I am wondering if anyone has tried replacing a Bose 901 Series IV equalizer with another multi-band graphic equalizer and "dialing it in"? Are there any schematics for the Bose 901 Series IV equalizer? My equalizer is starting to perform erratically after almost 40 years. Go figure.

Re: Problem with my Bose 901 equalizer serieIV

You probably have power supply filtering capacitors that have gone bad. Could be one or all of them.