10-21-2019 08:11 PM
10-22-2019 12:18 AM
It is actually my day job, to solve similar problems to this one.
The noise issue is most likely caused, by electrical interference. It is similar to the sound you notice, if you place your phone next to a speaker and receive a text message (it will be audible in the speaker).
With the CPU it's a similar thing, the CPU enable and disable power saving and you hear that in the speaker.
I could image, that while reassembling the Laptop, the service tech, didnt place cables exactely where they were therefore just slightly increasing the distance between certain parts of the circuit. This may have been enough to fix the issue.
So basically two different approaches:
a) Make sure the CPU doesn't generate the noises, via BIOS update
b) Make soure the sound assembly is isollated well enough from the noise
10-22-2019 01:46 AM
5 days since BIOS fix and the noise is reduced significantly, though I'll continue to observe the situation.
Also about 3.5mm jack, you should make sure that the noise problem is not reproducable via laptop speaker, if even laptop speaker produce noise, then I don't think checking audio jack will solve the problem.
10-22-2019 09:45 AM
Statements like these make me wonder where you actually get your information from...
Read the changelog for BIOS update 32WW found here: https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/legion-series/legion-y540-15irh/dow...
[Add] : Add the option "Slow Slew Rate for IA Domain" in bios setup menu
[Modified] : None
[Fixed] : None
[Modified] : Backlight will not off while S3/S4/restart if the brightness drops to the darkest level.
[Add] : None