765D fan runs when it shouldn't

[Jax184]

So I've finally got my grubby little hands on an ThinkPad 765D. Last of an era. And it's in superb condition too. Only problem is the fan.

With a fresh install of windows 98SE and the drivers sorted, the CPU fan comes on running 100% a few minutes after the machine is started and continues to run like that until the machine is turned off. Under the factory windows 95 install it would come on after a similar amount of time and then furiously fluctuate in speed every second of every minute until you turned the machine off. In neither case is the machine particularly warm, and the air coming out the back is pretty cool. Is there something I've overlooked? An app or setting to control the fan? Anything I can do to shut it the hell up? It's ear-piercing can be heard all the way down the hall.

If a software solution is out of the question I may build a custom temperature sensing fan controller into the unit as part of some other mods. But I'd prefer to fix the original one if possible.

[mnowell69]

well, if it's not a faulty temperature sensor on the board, maybe the heatsink is not connecting very well to the processor. in this case the sensor would sense that the processor is hot and switch on the fan, which of course would blow lots of cold air out 'cos it's not making proper contact with the fan. Naturally a bad sensor would achieve the same thing, but it's easier to check the heatsink.

[craigmontHunter]

Check the thermal paste - I have seen it dry out on older systems and they behave like that - the fan is able to just keep the part cool enough, but it is hard on the system - when you check the heatsink, I would reccoemend changing the thermal paste.