Trackpad stops working when Aux speaker connected

[SlickShoes]

I have been investigating an issue that I am coming up blank on from Google searches.

I have a MacBook pro, it works perfectly but when I plug in my Aux speaker which is also plugged into a power socket, the trackpad on the Macbook pro stops working, as soon as I unplug the speaker the trackpad works again.

Has anyone seen an issue like this before? It is also a Bluetooth speaker but even with Bluetooth OFF completely it still cuts the trackpad.

 

[Sanpete]

What MBP and what speaker are you using, connected by what port?

Does plugging the speaker into your MBP but not the power socket still cause the same trouble? Have you checked with a different speaker?

My first guess would be that your speaker is passing power that it shouldn't be to your MBP chassis, which is interfering with the trackpad.

 

[SlickShoes]

Hey, Yeah that was my thought, it only happens when the speaker is plugged into the wall socket for power. The speaker is always connected to the computer via AUX cable. I don't have another speaker I can test at the moment and it's not possible to just borrow one due to social distancing in my country.

Also the speaker is a Bose soundlink 3

 

[BrianBaughn]

I've never heard of this situation. That actually sounds dangerous…at least to the MBP. There could be a fault with the MBP's jack and it's a combination of the two that is causing it. However, although an aux cable definitely has an electrical current running through it…shielding or filtering in the speaker's electronics ought to be keeping the speaker from sending more if it's plugged in.

Do you have a multimeter? It would be interesting to see the difference in current on the 1/8" jack when plugged in.

The only thing that should disable the trackpad is the System Preferences setting that turns it off when a mouse is connected.

That's an older Bose product. I think the current models all charge via USB.

I wouldn't plug it in at all now if it were me. I'd also call Bose and see if someone there is aware of or can even understand the issue. Lobby for a replacement.