Weird noises from Lenovo T420

Hey guys :hi2: ,

I am hearing weird noises from my T420, I already disabled the fans, took out the ODD / DVD-Drive and tried if the sound disappears when I take out the battery and use it via charger (which somehow defeats the sense of a laptop ). I exchanged the HDD for an SSD, so this is not the source of the sound as well.

The sound is comparable to the sound my Win 98 laptop made while writing data, just that the sound now is higher pitched and varies its volume by, I suppose, the workload. It does not seem to have an allocalable source, but I would say that it is louder on the right than on the left (when you have the T420 sitting in front of you, with its display facing you).

I hope you can help me ,

Greetings, gunit

 

The sound is made by RAM modules or other switching circuitry. You could test with a different RAM module(s).

 

Thanks for your input Mike! Unfortunately I do not have any compatible RAM modules available here. However, I wanted to expand my RAM size anyways, so I will check this after I got the new modules by just putting the new ones in, this should show if the current modules are causing the noise (I'll have to wait for approximately a month before I get them).

In case this would not work, what could it be ? I researched it a bit and I now know that these whining sounds are usually caused by by-pass capacitors or back-up capacitors, it is called the piezoeffect - exactly what you described. The problem is that these capacitors are on the mainboard, PSU and GPU board. My notebook does not have a dedicated GPU, so that should be out, the PSU is external and I am having these effects while just running on battery, running on PSU with battery in and out - this should be out as well. The only part left is the mainboard then if my assumption is right ?

 

It is just CPU whine, very common with Intel CPUs running in low power states in combination with certain voltage regulator schemes. Nothing is broken, and it will not progress.