There seems to be a problem with the tone controls, specifically 'high cut', 'low cut' & '-20 db' switches also the 'tone on/off' switch. Whenever one of these is activated, even at 0 volume, a loud pop is heard and of the spkr relay kicks off momentarily. There must be a coupling cap somewhere that's not surpressing the transition noise that directly affects the mains output. Can someone shed some light on this. All other controls operate normally, no crackling of the volume pot or scratchy bass & treble controls. I'm stumped! Cheers, Steve
Pioneer SX1010 popping noise
Jan 30, 2007
2 Replies
Steve,
In older Pioneer receivers I've seen lots of leaky low value Sanyo electrolytic caps, usually 2.2 uf or lower, and 25 volt. I'd change them in the tone circuits, and at the input to the power amp, if they are present. These caps are usually a light blue-gray in color, and have a odd looking seal at the bottom, not the typical rubber, but sort of like a shiny black goo that dries hard.
Remember, it could be DC coming in before the switches, or DC getting out after them.
Regards, Tim Schwartz Bristol Electronics
Thank you for the hint Tim, I've always checked for bad esr on electrolytic caps in older amps, I'll check the ones you've pointed out. Cheers, Steve
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