CPU Fan

[folivieri]

I have a Dell Inspiron 518 Dual Core Intel E8400 3 GHZ 1333 FSB, 4GB Memory , Vista 32bit system. My question that i have is my CPU fan started making a humming/ buzz type of noise, not real loud just an annoyance ( a little). I did diagnostics to find out that i had an cpu fan error code 3700:11B incorrect fan speed. with cpu fan showing different rpm speeds like 1878 1875 etc. I don't know what the correct rpm speed is because the dell phoenix award bios doesn't show cpu fan speed or much of anything else, just basic system information. You cant change much either, had been told that Dell doesn't allow you to change much (locked) MOBO etc several yrs ago. My pc system is 3yrs old and i have upgraded the PSU, video card, memory, and CPU from E5200 2.5GHZ to E8400 3 GHZ both dual core. I upgraded the new CPU a few months ago with no problem with the fan until 3/1/12 that's when I began hearing the humming/ buzzing noise coming from the cpu fan. I did some research and replaced the cpu fan / heatsink, but when I did diagnostics again it still shows that error code, new fan rpm speed changed a few times in diagnostics, but I think the fan is fine. The new cpu fan is a Masscool 2400 rpm one (for LGA775) and doesn't make that noise and is quiet about the same as original one. So if my cpu fan is fine,why does it still say that error code 3700:11B incorrect fan speed. I don't even know the correct original stock cpu fan rpm speed, thought it might be 1800 rpm (from diagnostics), but not sure (didn't show in BIOS originally).  Upon further research on stock fan, the stock fan is a Delta electronics one, Delta Electronic fan model AFB0812SH, see article http://www.silentpcreview.com/article689-page5.html. The model is rated at 4000 RPM which i don't really believe is correct but you never know , my old fan wasn't loud but very quiet like the new one (Masscool model 8WT15-38) at 2400 rpm. My Dell BIOS (Phoenix Award Bios) is the latest version 1.0.8, old version was 1.0.3 version. Could it be something else?, no problems booting system, cpu temp fine, etc just that error code if i do a Dell system diagnostic. I would appreciate any advice/ recommendations Thanks Frank

[joy division]

The only thing I can think to say is try clearing CMOS and running the test again.

If your computer is running fine I wouldn't worry about it.

[folivieri]

Thanks Joy Division, I will try to clear CMOS and re run test.  Thanks

[folivieri]

I tried clearing the CMOS on the Bios (load defaults) and tried clearing by jumping pins on motherboard, and removing CMOS battery all to no avail.  I assume that the BIOS/ Dell MoBo is looking for the stock fan which supposedly had a rated 4000 RPM speed. I have a Speccy report prior to installing my new CPU and I noticed the original stock fan speed was 1874 RPM when I printed it out and the CPU temp was 54C.  My new CPU temp is and has been at 42C since installing the new cpu fan/ heatsink.  but I still have that error code of incorrect fan speed.  I'm wondering if a higher rated cpu fan or a new stock fan would do the trick. My system again is fine just so curious as to what it could be.  I think the MoBo is looking for that stock fan / or rated RPM speed.

[patio]

Was the replacement fan 3 or 4 prong as the original ? ?

[truenorth]

Sounds more like a sensor error than a hardware fault given the performance.Some BIOS (generally as manufactured originally) have the ability to do certain parameter checking . Such as fan speed. However not all fans that are often used in replacements have all the terminal necessary to provide the sensing value. Then the computer is looking for a value it cannot determine (find) and thus the error message. I am daily using a computer about the same vintage as yours that constantly is giving me an error message at boot relating to a fan NOT functioning. Which is exactly the one i replaced.This could be your issue as well. If your temps are within range and they seem to be then i suspect the absence of sensor data.truenorth

[folivieri]

My stock fan had a 4 prong, but new one is only 3. I purchased the new fan from a local computer shop and was told that the 3 would be fine.  I also tested a used CPU fan/ heatsink with a 4 prong from the  repair shop, but that fan was so loud and the error was still there. I took it back and then ordered the new CPU Masscool fan 2400 RPM rated

[folivieri]

Hi truenorth , how do i go about obtaining that sensor data??.  I only get the error of incorrect fan speed when i do the dell diagnostics only. Everything is else is fine, no errors or anything else when booting etc., just when i do a diagnostics.

[patio]

Prongs
Positive
Negative
Sensor
Speed control.

Unless you want to replace the fan again with a 4 prong model it's probably safe to ignore the BIOS warning...

[truenorth]

Just to take my last kick at the can and address your desire to "how do i go about obtaining that sensor data" patio has answered that. If your next desire would be to at least eliminate the error  message. In my case i can enter the BIOS and change a parameter to "ignore" the error.However it doesn't change the outcome as the very next time at boot the error message is there again. I have opted to just ignore the message.truenorth
P.S. It tends to indicate an additional fault when "I also tested a used CPU fan/ heatsink with a 4 prong from the  repair shop, but that fan was so loud and the error was still there." So whether a replacement 4 prong fan would actually give you back the sensor is questionable.

[patio]

I've seen 4 prong fans where the sensor and speed control pins we're reversed...essentially nuliffing both those functions...
You'ld think they'd all be standardised.

[folivieri]

Thank you both true north and patio for your help.  I will try one more time with another 4 prong CPU fan specifically for a Dell Inspiron 518  to see if that will do it.  If not then I will leave it alone, since there's no performance or other issues.  Again thanks I appreciate it.

[folivieri]

I'm looking to purchase a 4 prong, higher rated RPM speed Dell inspiron 518 compatible CPU fan to see if that will take care of that error code. My question is what fan would be best. I currently have that new Masscool 90mm 8WT15-38  2400 RPM rated 3 prong one. I looked into several models such as the Masscool 90mm 8WT15-17 Intel LGA775 Copper Base CPU Cooler with a rated 800- 2800 RPM 4 prong, compared to my current Masscool 90mm 8WT15-38 model.  I'm also looking into the Dell CP825 and JY167 Vostro 200/220 model CPU fans (was told its compatible), but I'm having difficulty getting the RPM information for the CP825/JY167.  Again I'm going to try the 4 prong and higher rated RPM and go from there.  Again any advice or recommendations is greatly appreciated.  Its just so baffling and I'm kinda determined to find out what the problem is and resolve it (peace of mind i guess).  Thank You again