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When powered on, the unit emits high pitched whooping sounds (see video). I opened it up, hoping to see something obvious, but everything seems fine for a 25yo device. It does this both on battery and on Wall plug. Suggestions?
I don't have access to an oscilloscope, just a soldering iron, multimeter and limited understanding.
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crwdns2934065:0crwdne2934065:0: 781.6crwdns2936485:0crwdne2936485:0
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@okeribok that does not sound like interference. It sounds like a bad power supply (MOSFET) or bad power amp. We’ll have to see the boards etc. to help you further. Attach some good pictures of your board to your question. Adding images to an existing question
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Try the multimeter on the speaker cones or output, and see if the voltage output fluctuates.
crwdns2934271:0crwdnd2934271:0 Jessica Parnelli Fawkes crwdne2934271:0
Thanks for the reply. I tried it and saw that it indeed fluctuates. My meter is digital, so exactly how much is hard to say, but I saw over 6V values. What does this mean?
crwdns2934271:0crwdnd2934271:0 Okeribok crwdne2934271:0
Maybe a damaged amp circuit? It could be thinking there's a signal, and amplifies to max, then resets. Or maybe interference from another device?
crwdns2934271:0crwdnd2934271:0 Jessica Parnelli Fawkes crwdne2934271:0
Yes, that sounds about right. there appears to be done sounds, but that gets mangled and only one channel works. Could it be a capacitor or something? Like replace one component and it works again? Is there a way to test components without removing them? There are no visual effects (leaks, discolouration, smells)
crwdns2934271:0crwdnd2934271:0 Okeribok crwdne2934271:0
You can add some ferrite beads to the wiring. May not fix it, but it should help prevent interference.
crwdns2934271:0crwdnd2934271:0 Jessica Parnelli Fawkes crwdne2934271:0