Question Strange cheeping noise when charging notebook

[carrotsandpeas]

Hello!

I bought a used MacBook Pro late 2013 15′′. It runs without any issues except when charging the notebook you can hear a cheeping noise. I have a late 2013 13′′ too and it does not have this at all. I almost sounds like the energy is sucked into the battery, as strange as it sounds, but I cannot describe it differently. What I could observe regarding this is the following:

• It seems to originate from the left speaker underneath the MagSafe port
• The connector is becoming really hot when it is charging. The connector on my 13′′ usually becomes warm at most.
• As soon as the battery is charged halfway the cheeping noise disappears.
• The fan does not seem to cause the noise, because you cannot hear it at all, once the battery is charged halfway.
• If you hover over the elements in the dock their size is increased. This causes the noise to become louder for very short duration. It sounds similar to the noise a HDD does when reading a data. You can hear it when scrolling in the browser too and doing stuff like that.
• There is a small dent on the top case near the MagSafe port, hardly visible, but with the right light you can see it.
• The battery only has 48 cycles on it, but it is missing 1/4 of its capacity already (from 8400 mAh to 6200 mAh). System Report recommends maintenance of the battery.

Do you have any idea what could cause this and how I could fix it?

Thanks for your help

 

[Darkbreeze]

https://appletoolbox.com/fixing-a-malfunctioning-power-chime-on-mac-and-macbook-devices/

 

[carrotsandpeas]

Thanks for the reply, but I do not think that the power chime sound described in the topic you linked is my issue, because I own an older MacBook Pro which does not have that power chime at all. It really does not sound like something the OS is producing or is intentional.

 

[Darkbreeze]

Does it always do it when plugged in if it's less than halfway charged, whether it's turned on or not, or only if it is turned on while charging?

 

[carrotsandpeas]

Good question! I just tested it. There is nothing audible when the computer is powered off. What I noticed is that when I put my finger across the power plug and the top of the case where the MagSafe port is, the noise is getting quieter. Perhaps it has something to do with - and I just throw that in there without much knowledge about it - grounding?
Also when you hover with the cursor over the dock, or open finder or the web browser and click around every time you do something you can hear this old school HDD reading sound for a second. That is weird because the 2013 retina model has an M.2 SSD built in. And its coming from the speaker too. Perhaps it is some kind of interference? I don't know, it's really odd.

The fan and the speakers both seem to work fine. I just listened to some music and also ran a 4k video to get the fan speed up. Sounds totally normal, similar to what I am used from my smaller 13'' late 2013 MacBook Pro.

 

[Darkbreeze]

Pretty weird, but at least it doesn't do it if you charge it while it's not powered on. So that is definitely better. Not sure about the other stuff but I suspect this might actually be some kind of capacitor squeal or feedback vibration of some sort. Either way, probably not going to be fixable without being taken apart and we all know what a bag of rotten apples that is.