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I bought a new Lenovo laptop, but sometimes used the power supply for my old Lenovo laptop. I just found out that the old power supply was the source of a very irritating high frequency sound (sample here). If I use the new power supply provided with my laptop, there is no sound. As it's rather convenient to have two power supplies, i would like to know the following:

Will using this old power supply damage my battery? (or some other parts of the computer? -- even though i can't see how that should happen)

(I have also tried to swap the cords going from the AC socket to the power supply -- it had no effect)

If you want to see the technical data for the two power supplies, see this image (old is left, new is right):

image

RasmusWL
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1 Answers1

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Over time due to thermal cycling the tiny wire windings of the inductor coil that is used in the battery charge circuit will micro expand and contract and the hot glue used to keep them together can give way a little. When the battery is being charged the circuit switches at a very high frequency, however the fine control needed to keep the current constant as well as certain combinations of voltage and load can cause the coil to resonate at a frequency in the audible range, thus producing a high-pitched sound. This should not be a problem normally and should pose no danger to your battery or other parts. If the sounds gets too loud however or the adapter is getting very hot, I would recommend you stop using it.

Karan
  • 57,289