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Old 10-31-2018, 03:35 PM
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Creaking sound from stereo

Hi guys, haven't been on this forum in years. I have a late 60s/ early 70s Magnavox astrosonic stereo that has this sound out of the left speaker that is kind of like moving a creaky door really slow. Has worked fine for a long time, the sound just started. Any ideas?
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Old 10-31-2018, 03:51 PM
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Are the electrolytics original? Some of those caps prevent oscillation or cause it when bad.
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Old 10-31-2018, 04:17 PM
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Quote:
Originally Posted by Electronic M View Post
Are the electrolytics original? Some of those caps prevent oscillation or cause it when bad.
Im almost 100 percent sure they are. The sound corresponds with bass, whether from the record player or radio. It spends most of it's time sitting and was played a good chunk of this weekend. Usually on bad caps, I just get the typical death hum.
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Old 10-31-2018, 04:31 PM
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I'd bet on lytics too - maybe a "motorboat" oscillation when a push-pull stage draws increased current due to increased bass volume?
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Old 10-31-2018, 04:49 PM
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Ill see if I can make a video of it sometime, then it may be easier to help diagnose, it has some pretty dirty controls, I may give it a shot, but it probably is caps.
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Old 11-01-2018, 11:45 AM
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https://www.youtube.com/watch?v=_XRP-GAcLwc
Here is the video, it went away overnight, and then came back after about an hour. Sounds like popcorn. Doesn't get louder with volume, but does become more rapid.
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  #7  
Old 11-01-2018, 02:37 PM
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Definitely bad capacitors Johnny you may want to change those a full recap is in order
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Old 11-01-2018, 10:19 PM
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After some diagnostics, turned out to be a capacitor on a small board for the output. Problem solved thank you all for your help.
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Old 11-07-2018, 09:00 AM
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Congratulations show me I'm fixing that I hope you enjoy your Magnavox I love that sound but Magnavox specially the tube type models solid state is okay but tubes are better going to stay in touch better
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