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I'm trying to help out with an MDS-51S that has two 4 channel ADC amps. When they turn the organ off there is sometimes a very loud pop. The normal suspect would be the mute relays on the input of the modules, however it still does it with all of the inputs unplugged. Any ideas John and others who may have dealt with this before? Bye the way I don't post much on the Forum, but I sure do respect all of the collective knowledge found here!
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Does it still do it if you turn all the volume controls down to zero? Also-- can you isolate the pop to just one channel, or perhaps to the four channels that come from just one of the assemblies?
My first guess would be a poor ground connection somewhere. Open up the amp cages and carefully re-seat all the push-on connectors. Double-check all the connections of every kind inside there. Check the small cap and resistor between one terminal of the filter capacitor set and the frame of the amp unit.John
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All excellent suggestions! I'm going back over Friday and will check each output with a small speaker to try to determine if it is an individual module or a whole 4 channel chassis. It sure sounds like some kind of voltage component being discharged on the speaker output. As you suggested, I plan to check the 1K bypass resistor that ties the amp ground to the chassis. I'm wondering if an output transistor were leaking or shorted if it would cause he problem. If I do find anything obvious, I'll sure let you folk know. Thanks again for your thoughts John!Comment
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