T61 Fan Pulsating About Once Per Second

[audioresearch]

I'm having a problem that suddenly appeared for no known reason (laptop was not dropped, no lightning storms or ac power surges-laptop
was just sitting on a table and had been working fine for years): on startup, a message appears that says "fan error" and the machine shuts
itself off in about 10 seconds, long before trying to boot Windows.

When the fan comes on, it pulsates-seems to be under power for about 1 second, then no power for about 1 second where it constantly
slows down, then powered on again for about another second where it speeds up, etc, ad infinitum.

I replaced the fan with a new one and the situation remained unchanged. I researched the fan and it appeared the one to get was 42W2462
which is what I got.

If I hit "escape", I can get around the "fan error" message and boot and run windows. Most of the time, the fan continues to pulsate, but
sometimes it runs constantly for stretches of around 10 or 15 seconds or so and then resumes the pulsating.

As a test, I ran the machine this way and it stayed on and worked fine for over 45 minutes, so I do not believe it is overheating. As a previous test, I ran the machine with no fan but with the fan heatsink still attached to see if the heatsink would carry away enough heat by itself. I did this twice and after about 3 to 5 minutes, the machine shut itself off which tells me the machine shuts down when it gets too hot.

I take that to mean that when I run the machine as it now is, where I get around "fan error" with "escape", that the machine must be getting cooled ok since the machine does not shut itself off.

If all of this is right, then the only problem I have is that I have to hit "escape" every time I startup and I have to hear a pulsating fan noise. I'd rather live with that than get another motherboard.

Nowhere in bios setup could I find any type of setting for the fan or even a display of the fan speed or any internal temperatures. My bios is version 2.26 (7LETC6WW).

I currently have a T61 type 7664-16U. It has the T7300 cpu (dual core 2.0GHz), nvidia NVS 140M graphics, 14.1" widescreen 1440x900.

QUESTIONS:


Are there any programs for the T61 that run under Windows or are there any fairly easy "tricks" so that I could just set the fan speed to maximum or maybe to some percentage of maximum that I could select? I haven't been able to find any programs yet. The one I found with Google all seem to be for models other than the T61 or for Linux which I do not run. I'm running Windows 7 on this laptop.

Do you agree that since I put a new fan in and still have the problem, that the problem is the motherboard?


Thank you very much!!!

[RealBlackStuff]

When you replaced the fan, did you also clean off and replace the thermal paste between CPU and heatsink?
If you just reused the old gunk your motherboard is in danger!

To check the temperatures and set different fan speeds, get TPFancontrol: http://www.staff.uni-marburg.de/~schmitzr/donate.html
Make sure to read the instructions!

[audioresearch]

I took your advice and installed & ran tpfancontrol. From what I read, not sure if it is supposed to work 100% with a T61, but this is what
happened:

I get a new display on the desktop and it indicates that at idle cpu is running about 68-70 degrees Celsius. I'm not very knowledgeable about what the temperature should be, but I am suspicious that 68-70C is too hot. Machine is just sitting there displaying Windows 7 desktop, but at the maximum brightness.

I've tried using the "manual" setting and have tried setting the fan speed to 7 which seems to be the max. Unfortunately, the fan still pulsates. I would have expected the fan to turn at a constant speed when "manual" was selected. I also tried fan speeds 0 and 3 in "manual" and got pretty much the same behavior.

Changing the settings to "smart" and to "bios" also did not make any really noticeable difference in cpu temperature range or fan pulsation.

Interestingly enough, in all configurations that I tried in tpfancontrol, the fan rpm always displayed as zero. Since the documentation I read about tpfancontrol does not indicate it is known to run on the T61, maybe I am seeing 0 fan rpm because tpfancontrol doesn't display it on the T61 or maybe there is a problem where the motherboard is not sensing the correct fan rpm, I have no idea.

The GPU temp range is about 55-56 C. Ambient room temp is about 67 Fahrenheit.

I don't think tpfancontrol would have any effect at startup of the laptop (before Windows booted) and so I expected to continue to see the "fan error" message at hardware turn on and it does indeed show up all the time at power on.

I tried playing some hi def video with sound and that made cpu temp rise to about 73C and gpu to about 60C.

Please give me your thoughts on the various temps mentioned above that I am now seeing.

Thanks very much again!

[RealBlackStuff]

I repeat my question: did you also replace the thermal paste?
My guess is no, your machine runs too hot.

[audioresearch]

Well, you've shamed me-yes, I admit I did not change the paste. But I promise I'll get some new paste and replace the old paste with it!!

The new paste will undoubtedly help somewhat, but I think the majority of the problem is the fan because those few times when the fan stops pulsating and spins fast, it has no problem lowering the temperature by a lot fast.

Is there any type of fairly simple fix where I could, for example, disconnect the fan from the motherboard and instead run a power supply voltage directly to the fan to spin it at a constant, fast-enough, speed? The pulsating fan is annoying to have to listen to. I never run off the battery, so a constantly running fan running down a battery too fast will not be an issue for me.

[RealBlackStuff]

Because T61 fans are so effective, they 'cool down' quite fast, but because your CPU also heats up very fast, this pulse cycle is starting.
Once you replace the paste, the pulsing should be over.