Dell :: Faulty Thermal Sensor

what i wanted wass to fix/bypass the sensor without having to replace the damn board. i couldn't even find a single post staing where exactly the sensor is on the board.
my problem specifically was that beer got spilled on the keyboard. after a while the machine shorted and shut off. I have a Dell Inspiron 9300, with a 1.73 ghz Sonoma CPU. i left the laptop off for two days so some of the liquid would dry out. after some problems and a dozen reboots i got into the bios, then finally through to windows. everything was fine except that the CPU was working at a very low frequency. also the fans were continually at highest speed. the CPU was being reported between 101 mhz to 503 mhz, depending on the software. it was being recognized correctly but showing to operate at 202 mhz in the system properties panel. what was really striking is that the notebook harware software i had installed was reporting the CPU temperature as 85 C. I tried various software to manipulate the CPU frequency to no avail. The temp was a constant 85 C, although i could tell that it was not even close to this temperature since i my laptop was partly disassembled and i could feel the surface of the heatsink with my hand; it was cool.

I finally surmised that the problem was with the thermal sensor on the motherboard. it had probably shorted or got soaked and was reporting the highest temperature it could as a safety measure, thereby limiting the CPU to a very low frequency and not allowing it to throttle above 503 mhz.

My last option, save for replacing the motherboard, was to find the sensor chip, clean it, dry it and hope that it would work again.

But this is not what solved the problem. somewhere on the net i came accross a code, that when entered on an Inspiron 9100 (an older laptop, with a different chipset) would bring up the Thermal Management screen or something like that, which is certainly not accessible via the BIOS. I was playing around with the settings on a program called Hardware sensors monitor, again to no avail, when i finally decided to enter this code:

FN key + zxcvasdqwer. almost the second i pressed z, or maybe after x, the high speed fans shut off! after a short while they kicked back into operation but at a low speed, just like they were supposed to. the program hmonitor began reporting a more realistic CPU temp. i tried to play a high-def movie file and finally it played normal, without any lag or stuttering! as i played it, the fans kicked into higher mode, and the temp which had been steadily rising, began to drop. the program, and most other programs were still reporting the cpu at 202 mhz, windows system properties as well. but since it was playing a 720p video file normally, it had to be much higher than that. i did a reboot and voila!

all monitoring software are now reporting the CPU at 1.73 ghz. the system temperatures are perfectly normal, and at idle the CPU goes as low as 20 degrees C. The software Speedfan, however, is still giving an error regarding the sensor chip on the motherboard.

I seemed to have fixed the severe thermal sensor problem by a few keystrokes, without having to replace the motherboard or even the sensorchip. in fact, i didn't even have to find the sensor node and clean it.

I came accross more than a dozen people who had a very similar problem to mine, with the temperature being reported at 85-86 C, for no reason. At least those who have a Dell notebok might be able to solve this problem.