Long story short, I got a new laptop to replace my long-aged MacBook
. I got a Thinkpad Yoga from Lenovo which is just about perfect for me - with one minor problem: the headphone jack. For some odd reason, there is always a high pitched squeal that can be heard using headphones - especially on the right side. As I tend to listen with headphones a lot, this can get quite irritating after a while. The problem manifests itself worst when the laptop is actively charging which makes me think it is some kind of interference from the charging circuitry at work. If possible I would like to eliminate this squeal, and just wanted to ask a few questions and get your advice.
I haven't taken apart the computer yet, but there are a couple pictures of the motherboard out there. In
this picture it shows the battery cabling going over part of the PCB that leads to the headphone jack (far right). I found an
eBay listing with photos of the flip side of a similar PC, which show traces going to the headphone jack that pass under the battery cables.
So my first question is - is it possible that the current going in and out of the battery can cause this type of interference? Or is it more likely to be the charging circuitry itself?
Secondly, if I were to put some insulated copper sheeting between the battery cables and the PCB (if that is likely the issue), could that cause potential issues down the road? I don't know how EMI would react in this situation.
Thanks so much for your help! It's a long shot, but hopefully there is something I can do to fix this problem...