High pitched squeaky noises coming from T42

When I have my T42 running on AC power I hear nothing from the laptop, but as soon as I run on battery it makes a high pitched squeaky noise coming from somewhere on the laptop. What is it?

 

can you make a recording? Is it from the fan?

 

I can't make a recording right now but I can tell you that it sounds like it is coming from the fan vent.

 

most likely the fan is needs a bit of cleaning (most likely it needs to be changed). It seems that you got yourself a problematic machine.

You can reach the fan by removing the keyboard.

 

Ahh yes, it has caused a few problems but all of which are fixed now . I've opened it a few times and saw some dust on the fan and haven't really been bothered to clean it. Though the sound doesn't happen at all when it's on AC power.... why would it do it on battery power and not AC power?

 

properly your fan is spinning at different speeds under these different power modes.

Download TPfancontrol, and try to test the fan by going through 0 to 7 speed mode, to see whether the sound problem comes back.

 

I already tried this hmm, still makes the sound on every setting from 1-7

 

other than getting a new or refurb heasink/fan, i am not sure what else to advise you at this stage.

 

Are you sure this sound is from the fan? Could it be the high-voltage transformer driving the display? The voltage drop from being unplugged might cause transformer whine.

 

I have no idea. Other than it being annoying should I be concerned or is it still all functional?

 

you shouldn't be concerned until it fails.

 

It's def not the fan.

Google "lenovo laptop whine"

 

that is for Core 2 Duo processor and later. This problem was present when the Pentium M was used as in the case of the T4x thinkpads.