# Squealing Genius speakers (damaged)



## Renoise (Jan 9, 2017)

Hi there,

not sure I have chosen the right section as my question is about repairing a faulty speaker in general. I have had these Genius SP-HF1201A (2+0) speakers for a few years and they always worked fine, I actually loved the sound. One day after switching them on the left one (the main, powered one) started emitting an intense high squealing sound. They still sort of work, but every other sound is totally lost in this high pitched squeal.

As they are no longer being sold, I would really like to repair them, but am unable to figure out which part failed and needs replacement. Having downloaded a service manual, I was hoping to find help there, yet no such luck. https://www.yumpu.com/en/document/view/21390822/sp-hf1201a-service-manualpdf-genius

There are two small PCBs in there, one connected to the in/out ports and one apparently power related, my guess is the problem lies in the latter. I know very little about electronics but I can solder, so I have managed to repair a few gadgets, but here I am lost. Could anyone, please, provide any insight or hints at what could have gone wrong?


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## octaneman (May 13, 2009)

Hi Renoise 

From the information you have provided, by looking at the schematic diagram the squealing is most likely coming from one of the OP amps (operational amplifiers) not working properly. Its causing a feedback loop which could be heard through the speakers. These op-amps have capacitors that are connected to them, these act as filters on the circuit for high and low frequencies. If you know how to use a multimeter test the capacitors (all of them) on the speaker in question, and then you will need to take voltage readings on the pins of the op-amps in order to isolate which one is faulty. 

If you could post a picture of the circuit board it will help with the diagnostics.


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