Question Motherboard beeper beeping when sleeping

Oct 27, 2020
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A friend gave me a Dell Optiplex 7020 SFF to mess around with, and it's exhibiting a strange problem: there's a piezo buzzer on the motherboard that is beeping steadily and faintly when the machine is sleeping. It's almost inaudible, in fact, and I was ready to chalk it up to coil whine from the PSU. I replaced the PSU though, and it continued doing the same thing. Using a rubber tube to my ear, I tracked it down to this piezo buzzer that, I assume, is responsible for beeping out BIOS error codes on startup. It's almost funny: the word "BEEP" is silkscreened onto the mobo next to it...and that's exactly what it's doing! It's so faint it sounds like a truck backing up three blocks away (originally, in fact, I thought it was coming from outside of my house!). It only does it when the machine is sleeping, exactly in time with the flashing power light; anytime the power light flashes off, the beeper beeps.

Any ideas as to what I can do about it, short of packing sound deadening foam around it, which I may do, anyway?
 
Oct 27, 2020
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Thanks for the suggestion. Unfortunately, it didn't solve the problem. The power troubleshooter found no problems, and the beeper is still beeping on standby. I suspect the assumption in that thread you linked (though it didn't say this anywhere) was that the beeping was coming from the power supply. While this was what I thought initially about my machine, it turned out not to be the case.
 
Oct 27, 2020
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Went for the unorthodox solution: a small piece of electrical tape applied to the top of the beeper. It blocks the hole in the top of the resonator case of the piezo buzzer, itself, and almost completely stops the beeping noise. So the beeper is still beeping away merrily, I'm sure, but I can't hear it anymore.